TLDR; The keypad has left me extremely satisfied. Very convenient, huge flexibility in customizing the keys (in general, not just for gaming), almost completely silent, no input lag. However, the price is a bit steep, definitely NOT worth so much money even though it is (in my opinion) the best keypad I could buy (in terms of my needs). Note that I used the keypad as a RIGHT-HANDER with my left hand and it worked perfectly for me. I don't know if it will suit someone in the opposite direction.

For those who use controllers; You can prioritize a controller through Windows so that the Tartarus does not "freeze" your controllers while playing a game (this only happened to me in FIFA, all other games did not have any problems).

Detailed review:

Keys: The keys are very enjoyable to use and press, quite sensitive, and without any issues with Inputs (input error, input lag, input repetition etc.). The same goes for the scroll wheel, as well as the directional tab it has on the edge. The keyboard design is easy to read, you won't see a button and wonder "what is this?". Finally, the keypad comes with optical switches, which are generally "better" (in a way) than mechanical switches for gaming.

Size and construction: The size seemed okay to me, somewhat large, although I know that I generally have "small hands", which made me have to stretch my fingers to reach some buttons. After a while, I got used to it, and now using it is relatively fine. The construction is also very good, it is not heavy at all (you can lift it with your little finger) but you don't feel like it's "cheap plastic" or "Chinese". Finally, it comes with a USB cable of about 2 meters, which personally covers the distance from the floor to the desk to connect to the PC.

Comfort: What can I say about this area, really excellent. I have wrist rests for my hands on the normal keyboard as well as on my mouse, and they really don't compare to the Tartarus. Really very comfortable, as I think about leaving my hand there when watching a video. Note here that you can generally change the position of the wrist rest if it doesn't suit you, as it is detachable.

Keypad & Synapse: I generally don't have a good relationship with Razer's software. I dislike it because several devices I have actually "worsen" in functionality when Synapse is running. However, I have not encountered any problems at all, it seems to work normally, even with this "infamous" and unstable program.

Accessibility: The keypad comes with 3 default keymaps.

The 1st keymap replicates the classic functions of a keyboard, as you would need them in most MMORPG games (i.e. WASD, QWERT and numbers, among others).
The 2nd keymap comes as an Xbox controller, where the keypad buttons replicate the buttons on a controller.
The 3rd keymap comes as a joystick. Whatever applies to the controller, applies here as well.

None of the above removes the keys from the keyboard or controller, etc. Both will do exactly the same thing.

Overall, it is plug-n-play, but if you want to customize bindings on the buttons through the Razer application, which automatically downloads (but you can choose not to have it if you don't want it). You simply won't have the same level of customization of the buttons through other applications like reWASD, as far as I know).

Adaptability: Here, the product is truly excellent. It comes with 20 analog buttons, and 32 total programmable "movements" per profile. You can load 8 profiles, which you can change very quickly by simply pressing a button on the edge of the product, which means that in reality you can have a huge range of custom buttons to use AS you want.

For example, in the first profile, I have loaded all the shortcuts I need to do tasks (as you can see in the photo I uploaded (https://i.imgur.com/ElkuHef.png) I have a button to open Viber, another for Outlook, another to do 4 functions together (Shift + Ctrl + Alt + Z). In the second one, I have put everything I need for the games I play, which is extremely convenient there as well. It really offers me great comfort, and it's like playing normally with my keyboard, but... better :D Finally, in the 3rd, and last, profile I have, I use it for shortcuts in various programs for school (e.g. photoshop, word, PowerPoint, SPSS, excel, etc). The quick and easy switching between profiles is really super useful and "solves" your hands.

Price: Despite all of the above, its price, as much as we try, is high. It is one of the most expensive in the -Greek- market, and Razer seems to take advantage of the fact that it monopolizes the market with so many high-quality keys. I don't think it will break soon, but if it does, it is difficult to replace, as 130+ euros is quite a bit.

I will probably return for a review next year, to talk about the product's longevity, and if it maintains its quality.

Usefulness: It is aimed at people who either work with software with many shortcuts (I fall into this category myself) or need an advantage in "competitive" gaming (don't ask me, I'm a noob, for advice in this area see other reviews). Beyond that, the product is certainly a comfort, and certainly not aimed at the "general/everyday" computer user or the "casual" gamer.

Conclusion: The truth is that at first I hesitated with the purchase - I thought maybe I made a foolish investment in something that is not very useful. I was wrong, not only does it greatly help me, but it helps me extremely in my productivity and the speed of my work. I did not regret my purchase, and I hope it will make me look good in the long run.

Review Update 15/05/2024: Nothing has changed from what I have said above, even with many hours of daily use. I have loaded it with 8 different profiles with different shortcuts, and it really doesn't notice anything, it does everything perfectly and as I expect it without any problems. I now use it even on my laptop for all kinds of uses, e.g. gaming & shortcuts. What really deserves to be praised again is the pad that remains divine in comfort without any signs of wear.

Okay, I feel like I need to do this evaluation in order to save someone from wasting their money on the Tartarus Pro. Why am I saying this even though I gave it 4 stars? Read below.
First of all, as a keypad, it is excellent,
• solid construction
• wonderful keys (analog optical switches)
• dual functionality of keys
• adjustable key activation
• unlimited macros / 8 quick profiles.
Apart from all these good things, I encountered a "problem" which obviously is the fault of the Tartarus but not really. What do I mean? That's how it is factory-made.
The computer recognizes it as a controller, so when you try to play with a controller, it doesn't work at all. I tried it with an Xbox One controller and a PS4 controller. In short, the only solution to this issue is to connect the controller before turning on the PC and then connect the Tartarus. It's a matter of priority. For someone like me who constantly plays with a controller, this is a big drawback. However, if you don't play with a controller, I think it's worth experiencing what the Razer Tartarus Pro has to offer.