I have it for a year. Initially with terrible DSL and now with fiber optic.
I don't use the wifi at all because where the wiring ends, it doesn't give a signal no matter what equipment you use.
1) It never needs a restart. Not even when it switched from DSL to fiber optic.
2) If you feel like digging, it has incredible capabilities. You can connect to VPN from your mobile, it's a telephone center with an automatic answering machine, fax, and it can be used as a base for wireless phones. Your mobile can be used as a landline wherever you are. It supports smart home device management, although I haven't used it yet. It takes a hard drive to access files. It provides management when you are outside the local network. Priorities for devices and access restriction for each device separately. You can open access to devices within the network from the outside.
LAN port 4 becomes an isolated VLAN for guest access.
Plus continuous upgrades with new capabilities.

Truly a reliable tool with capabilities that fit a business, with zero management cost.

If you don't plan to utilize all of these, I'm sure there are very good and stable solutions with less money. But with what it offers, it replaces equipment of ten times the cost if you utilize them.

I have set up the router for 10 days now. It is worth noting that I am a COSMOTE subscriber! I did not see a difference in speed, but the difference in stability compared to the speedport plus is like day and night! The motivation to change it was that due to work from home and general use (4K streaming, COSMOTE TV, gaming, etc.) I needed stable internet! With the speedport, I had frequent disconnections and the worst part was that most of them were "hidden"! That is, the router showed synchronized, but in the interface, the CRC & FEC errors were showing millions and increasing dramatically per second, so I basically had to restart it manually to "stabilize" it! Now, after these 10 days, it has not "hung" even once and has not produced a single error! Finally, I just want to say that when I first set it up, I didn't need to do anything at all! No codes for telephony, no codes for the internet!! I simply plugged the cables into fon 1 for the phone, fon 2 for the alarm return, and DSL for the internet, and after 2 minutes, it automatically synchronized without any problem! Then I removed fon 1 because I "connected" the wireless DECT and saved another cable! Conclusion: the Fritz is worth every euro you will pay because above all, you don't have to worry about stability!

Owner of the FritzBox 7590 (international version) here for a year and recently also the 7530 AX. I had the 7590 at home for about 9 months to test it and then I placed it in the office, replacing it at home with the 7530 AX. Along the way, I paired it with the FritzRepeater 2400 and the FritzFon C6. I have to say that initially I was simply satisfied (in terms of its price) with its performance at home, but the device impressed me and truly "shined" when I placed it in the office. The 7590 is ideal for an office environment (especially a small office) where it stands out mainly for its ability to function as a telephone center (and more). I believe that unless in exceptional cases, it is not worth spending so much money to buy it for your home, which is why I now have the 7530 AX at home (purchased for €130 with some coupons and a promotion). The premium you pay for its price cannot be justified for home use, but it is equivalent to what it offers in a professional environment, which I will mention below.

First of all, the 7590 is quite large in terms of volume, much larger than the 7530 and larger than the Cosmote Speedport. Both lines it was used on are Cosmote VDSL 50, so as soon as the 7590 was connected to the line, it immediately retrieved the telephone line information and the phone worked right away. However, in the office, this did not work immediately and I had to call Cosmote's technical support so that they could remotely "send" the telephone line information and make the phone work properly without my intervention. Of course, even without the phone, the router had normal internet from the very beginning, it just didn't "catch" the VOIP codes for some reason. I recommend everyone to keep a backup of their router settings (SYSTEM>Backup), so that if you encounter any problems with the telephony and the settings are lost, you can restore them immediately with a restore without having to call technical support.

Its internet function is flawless (for lines up to 300 Mbit/s VDSL and supervectoring (35b)). Stable internet with speeds about 10% higher than the nominal line speed, and mainly without disconnections and restarts (a common phenomenon with the OTE Speedport). For problematic lines, it has settings to prioritize stability over speed. I think it is the only AVM router/modem that supports ADSL, ADSL 2+, VDSL, analog, and ISDN telephone lines.

Its WiFi (4 MU-MIMO antennas) is good and stable, supporting WiFi 4 and 5 on 2.4 GHz (800 Mbit/s) and 5 GHz (1733 Mbit/s), but it is not the feature for which one should buy it. It is certainly much better than the WiFi provided by routers from service providers. If someone, for example, is a gamer and is satisfied with the internet they have from their router but wants better performance or greater range in their WiFi, then they should look elsewhere, where they will definitely find something more economical. Personally, with good range extenders and TP Link routers, I have seen greater WiFi range and equally stable performance compared to the 7590. I installed the FritzRepeater 2400 in my home (90 square meters) to ensure a lossless WiFi 5 GHz connection from one end to the other, indicating that the router alone, located at one end of the house, was not sufficient for the 5 GHz network. The positive aspect is that they work flawlessly together, creating a stable Mesh network, but don't expect the signal to reach the neighbor's house. There are numerous settings for the wireless network, allowing for extensive customization. The guest network is very good and it gives you the ability to print an informative card, for example, for the reception area in an office, so that clients can easily connect to the WiFi without asking for the password, using a QR code. A nice touch is that as soon as the connection is established, it displays a greeting message with your own logo, which users need to click OK on to complete the connection. There are many settings and diagnostics that will satisfy everyone.

As for the telephone line, the 7590 can easily meet the needs of a small office, justifying its price as it does much more than a simple WiFi modem/router. Firstly, it functions as a telephone center, providing clear sound (HD telephony if supported by the provider). By activating the ISDN circuit from Cosmote (remotely, without the need for a technician or additional equipment - note: OTE, although it has the technical capability, currently does not have a product that provides a second and third VOIP telephone number, so if you need additional telephone numbers, the ISDN circuit needs to be activated, as informed by a technician from the headquarters), a second telephone number appears in the settings, which can be managed as desired. For example, you can set the analog device connected to the FON 1 port to receive calls from the first number, the device connected to the FON 2 port to receive calls from the second number, and all telephone devices to make calls from the first number, which includes all the free calling packages. Extensive customization can be done based on individual needs, and it can also function as a DECT base, allowing wireless telephones to be connected to it, which can also be customized in terms of how they receive and make calls. There is also a third telephone port on the side, of the TAE type, which is essentially a second output of the FON 1 port and not a FON 3 port. Furthermore, it has an integrated phone directory, which can be synchronized with your mobile phone (supports CardDAV standard as well as synchronization via Google and iCloud), although its major drawback is that it does not support Greek characters (hopefully in the future). It has a complete list of incoming and outgoing calls. It supports FAX functionality (of little practical importance nowadays) as well as an answering machine (specifically up to 5 answering machines), which allows for scheduled operation and forwards voice messages to your email. Alternatively, you can set a simple greeting (for example, in case someone calls during "crazy" hours) and terminate the call after playing it. Through the settings menu, there is a plethora of options for call forwarding, blocking, waiting, busy indication, caller ID, number hiding, and many more. An extra and valuable feature is the free VPN creation and remote use of the 7590 telephone line from your mobile through the FON application, wherever you are. For example, you can be at home and receive and make calls as if you were in the office using your mobile phone, taking advantage of the free landline talk time.

A very important feature (in the context of functioning as a telephone center) is the easy addition and operation of network telephony devices (IP). I added a GrandStream network telephone device relatively easily, which works seamlessly both via Ethernet cable and WiFi. The process was simple, and with the addition of network telephony devices, you really realize how "professional" the fritzbox device is and how much money you can save with a device that is literally all in one! The operation of the network telephones works as expected, fully utilizing their capabilities and saving me from the need to purchase a telephone center.

As for its function as a router, it has all the expected settings for full customization, and with the connection to the two USB 3.0 ports, you essentially turn them into network drives with access to their contents remotely through MyFritzNet. It has the ability to turn a simple USB drive into a NAS to manage it either as a media server or as a simple network shared drive. It is worth noting that it also has about 350 MB of free internal space (in contrast to the 7530 AX, which only has 9 MB), which is mainly intended for the answering machine, phone directory, etc. It has 4 Gigabit Ethernet ports (which can also function as regular 100 Mbps ports), the fourth port can also operate in Guest Mode (!), and one WAN port (which can also function as a regular network port) for connection to another modem/router or, for example, an ONT for fiber optic connection at home.

Its capabilities do not end here. In summary, I mention capabilities for Smart Home with AVM products, media server for podcast playback and web radio, alarm, parental controls, DECT Eco, Do Not Disturb function, and more. AVM has a huge support database on its website for problem-solving and how-to guides that will cover anyone's needs. The MyFritzNet function is very important, as it allows remote access to the operation and settings menu of the 7590 as if you were on a network computer. The settings menu is detailed and user-friendly with a wide variety of options. It is one of the most user-friendly devices I have used, with numerous updates and reports.

The capabilities of the 7590 are not limited to the above (I have omitted several), but the most important thing is that AVM constantly enriches them as they do not abandon the product, which is not new. For example, recently they added WPA3 regarding the security of the wireless network. The five-year warranty for the product is significant and relieves any concerns. Excellent product, stable and reliable, at a high price not because it has top performance, for example in WiFi, but because it has a plethora of features, excellent support, and is mainly justified if placed in a professional space and you are interested in comprehensive telephone line management.

UPDATE 15-10-2023:
Three years after its purchase, the 7590 works flawlessly without any problems. I consider it a "must" purchase for SOHO environments. For office environments, it is an all-in-one device, with a price that is really low for everything it offers, combined with top-quality construction and amazing support from AVM.
Note: for those who use the router as a base for a wireless phone, make sure you don't have another wireless phone base next to it, as it affects the signal and range of both.

There isn't much to add. Because the comments played a crucial role in my decision to purchase this router, I am leaving my own comment as well.
The modem is a very good tool. I installed it on a cosmote 100 fiberspeed line. Plug and play. You don't have to do anything since it works perfectly with it and automatically downloads the DSL and VoIP configs with the first handshake. It replaced the Asus ac68u, which, although a good router, disappointed me on the 100Mbps line as it synchronized 10Mbps slower than the speedport + with default settings, and when I increased the speed to the levels of the speedport through DSL tweaking, it brought crazy errors. It synchronizes 2Mbps higher than the speedport with zero errors for the past 2 days.
To be honest, the 7590 was my last choice as I was flirting with routers that have more capabilities for the same price (Linksys, Netgear, TP-Link). But let's face it, 200+€ is not a small amount, and instead of spending it on a router, it's better to go for something tested on Greek connections/providers. You just need to know that it's not the gaming router that will impress with its performance and countless capabilities. Its UI is simple, user-friendly but indifferent. BTW, there is an app for Android/iOS that essentially redirects you to your Fritz's page. Personally, I'm bothered by the lack of QoS and instead, you find a priority function for apps and devices that didn't impress me as I worked with it. However, these are not reasons to take away a star because at the end of the day, I just want stable, quality internet, and the 7590 provides that for me. Plus, the telephony capabilities are worth it. Just for your information, AVM is well-known in Germany, where in 2010 it accounted for over 60% of routers sold for internet and telephony services in the country.

In problematic situations - VDSL2 standard lines do not increase errors and keep the line stable.

2. In 200Mbps connections, OTE's Plus (in 35B mode) increases errors on the Modem side, not the DSLAM side (according to OTE's Monitor), resulting in the IP layer dropping after 1-2-3 days but maintaining synchronization. With the Fritz, you forget about this problem.

3. In the company, we had internal wiring issues, and OTE's Oxygen at 100Mbps had many problems and disconnections. The DSLAM with vectoring actively synchronized one line, the other would drop, the other would synchronize, and the first one would drop (in a loop). With the Fritz, everything is perfect... (now we have fixed everything as well).

4. It has an integrated mechanism to synchronize the line below what your provider's profile specifies in case you have an issue.

5. In the office, OTE's telephone lines were added as a backup to 3CX. Leave the OTE SIP Account active in the Fritzbox and create a new profile in the Fritzbox LAN/WLAN device (same profile as the one used for the AVM application, for example). This way, the use of a device like the Beronet Gateway is not necessary.

6. It has an integrated Fax with forwarding to email, works perfectly.

Although you are probably tired of seeing it, I will repeat it: If you have Cosmote, it is a choice like no other. The definition of Plug & Play. Personally, when I took it out of the box, I connected it to the DSL alone without any devices on it (neither ethernet nor wifi) and within 5 minutes without opening the administrative environment, it started up, connected via TR-069 (CWMP) to the OTE servers and received user, pass, and telephony on its own. Then I connected a TP-Link powerline hub with two nodes on top of it and the router detected them, displayed them as powerline devices in its menu, automatically assigned them static IPs, and now I can see the status including the transmission speed of each node directly from the Fritz. Next was a Motorola landline phone with DECT. The registration process is very easy, although I didn't keep it since its base is next to the router, so I decided to keep it wired. However, one thing I noticed is that when the other person hangs up the phone before you have a chance to answer, the device continues to ring for 5 seconds. This only happens with DECT and not with a wired connection. If you don't want to have a landline phone running and rushing to answer it, you can completely disable the device and download the Fon application from the company that forwards all landline calls to your mobile device and you can answer from there. The calling numbers are automatically synchronized with the contacts on your mobile device so you know who is calling you. The ethernet ports are remarkable because through the menu you can individually configure each one to operate at either 100 or 1000mbps, and the integrated WAN port not only serves as a futureproofing method when OTE decides to bring us fiber optics, but also as an additional LAN port, making the total number of ports 5. The LAN Guest Mode function allows you to define LAN port 4 as restricted in case you want to share access with someone outside the family. Personally, in a home environment, I don't see many people using it, but I have it enabled in 100mbps mode when a friend comes over and connects their laptop, so they don't have access to the other devices on the network, as well as the media server. Since I mentioned the media server, I have an external 1TB Toshiba hard drive connected with USB 3 for access from all network devices, and I can say that it works flawlessly from my Windows 10 computer to an old LG Smart TV from 2014, and it is convenient if you don't have money or space for a regular NAS. SoC from Qualcomm that works perfectly with the Intel AC9560 network card on my laptop, reaching the maximum 1733mbps it can offer (via WiFi)! The range is satisfactory, especially for indoor antennas, and the band steering from 2.4 to 5GHz (I have the same name on both) is fast and uninterrupted. I haven't had it for long, but with all the things I've heard about its stability, I'm not worried. If it disconnects, I will mention it, but so far, after 7 days of synchronization, it reports 13dB SNR, 6 Attn, 110/11mbps with a distance of 85 meters from the cabinet. It doesn't surprise me that it has 0 errors since it's not the most challenging conditions. This router proves that the operating system is as important, if not more important, than the hardware. After trying many routers (some more impressive on paper than this one), I believe that this particular router offers the most comprehensive and enjoyable experience with its beautiful and user-friendly menu, Plug & Play installation, and many useful features, some of which I haven't even mentioned in this review, which could easily become a whole book. In conclusion, I agree with a friend who mentioned in another review that it's not worth buying anymore, as a WiFi 6 version will be available soon with a small price difference. Personally, I'm not interested in WiFi 6 yet, and seeing that the modem from Cosmote was not satisfying, I bought this one and I don't regret it.

UPDATE 24/8/21:
Apart from a power outage and two firmware updates, I haven't seen it desynchronize from DSL EVER. One of the two updates I mentioned earlier (7.27) fixed the fragattacks vulnerability in WiFi, a fix that I can guarantee no provider router has received yet, and the other one (7.28) brought some more minor bug fixes. Since I wrote the initial review, I have received and connected a kit with three Panasonic DECT phones, and although I mentioned a small problem back then, which had to do with the phone not stopping ringing even though the line was closed, this problem does not exist with the new phones, and everything is registered flawlessly and steadily in the router's DECT station. Finally, I noticed something ridiculous but noteworthy. There is an option in the router's menu for automatic adjustment of the indicator brightness based on the ambient lighting. If there was any doubt that this is an over-engineered German product, it must have been lost with this detail. In short, having used this product for a while now, the final conclusions I wrote in the initial version of the review still hold true.

Another happy owner. With COSMOTE connection, I replaced the plus which for some reason had several interruptions in the last few days and with working from home (2 of us) plus my child's online school, it had caused me several problems.
Therefore, I made the decision to spend the money on something with such good reviews that allows me to completely get rid of the speedport plus.

The device was set up VERY EASILY, you choose the country, it prompts you to choose a provider (with options for COSMOTE or VODAFONE), it restarts and after a while, everything works. That simple! It didn't even ask me for the internet password! It locked 1mb more than the speedport 220/22 and for the first time, I see a speedtest of 200mbps even on WiFi!
The WiFi is very stable and the range is better than the plus. I was experiencing problems in some areas of the house which I no longer experience with the Fritz. I also noticed that it handles the switches between 2.4/5 Ghz much better.

Answering machine, central unit, media server, NAS, etc., I haven't used yet to have an opinion.

I connected a Panasonic KX-TG1611 to the DECT station (very easy process) and the date/time did not show on the screen and the caller ID did not work. As soon as you received a call, it showed the caller's number for half a second and then disappeared. It is likely that due to these 2 issues, you won't see missed calls on the device either.

Among other things:
[+] Those who did not have another router before this one will never know what disconnect means.
[+] Media server detectable even by old TVs (DLNA, UPnP AV).
[+] NAS server.
[+] Phonebook contacts with synchronized photos on all DECT devices that support them.
[+] Blocking of phone numbers.
[+] Blocking of hidden numbers.
[+] Custom answering machine messages.
[+] Connection to the router's network via VPN (IPSec & WireGuard).
[+] 2xUSB 3.0 for printers, storage devices, and 4G dongles.
[+] Remote sending of magic packet to activate devices that support Wake-on-LAN.
[+] Device prioritization.
[+] MU-MIMO.
[+] Fax to Mail.
[+] Myfritz.net subdomain (with the ability to issue a free SSL certificate) corresponding to the router's current IP. In case of an error during issuance, if your line is behind an upstream firewall, it should be temporarily disabled in consultation with the respective ISP.

[-] Complete lack of Greek language, both in the menu and in the mobile applications, despite several requests and negative reviews towards AVM on PlayStore. Take the trouble to make a few more, maybe they will understand at some point that the world is not only made up of seven countries.
https://play.google.com/store/apps/details?id=de.avm.android.myfritz2

For those who have Oxygen or Speedport:
[ ! ] Stop asking your known ISP what is causing the continuous disconnections and drops. They will not admit the obvious, nor provide a solution.

For those who have Raspberry Pi and cannot see it through Ethernet:
[1] Connect it via WiFi.
[2] Assign a static local IP to the Raspberry.
[3] Connect it with a UTP cable, disabling WiFi.
[4] Manually assign the Raspberry's IP (from step 2) and the FRITZ's IP to the eth0 interface of Raspberry Pi OS (in Network Preferences).
[5] Restart the FRITZ as well as the Raspberry.