Update3: I bought an Amazfit that makes Huawei's ecosystem look ridiculous. Installation of apps and modules on the watch and on the phone app.
Food and calorie tracking with AI.
Of course, there are no issues with iOS and you have full control over which notifications you receive on the watch and which you don't.

Update2: After one month, the color came off the metal part of the strap. It doesn't affect its function but it affects my mood... Combined with the other restrictions of Huawei and the bans imposed by the European Union, I would characterize this purchase as a failure.
I relied on good reviews—which, notably, NOT ONE mentioned the restrictions that exist on iOS.
For me, Huawei is off the list as a future option.

Update: On iOS, you can no longer install free watch-faces as of August '25.

Coming from a Garmin Fenix 8: The Huawei, to my great surprise, has high quality even in the packaging. It is lighter and doesn't bother you even while sleeping, unlike the Garmin. Its menu is also more user-friendly (I won't go into other comparisons, different categories).

Negative for iPhone users: You can't stop all types of calls (even viber/whatsapp/telegram) from ringing on the watch even if you completely disable notifications. It's inconceivable, extremely annoying, and almost a privacy breach. I can't understand what the hell they were thinking. I hope they fix it in a firmware update because it is UNACCEPTABLE.
Also, when you turn on the speaker on the iPhone, the watch is selected since Huawei has obviously made it appear as an audio accessory...

Let's start with the basics... It's not a smartwatch, it's a fantastic fitness tracker with some extra functions on an Android phone.
I will speak as a user syncing with an iPhone device.
Positives:
Long battery life compared to the competition. Truly impressive, close to 10 days+.
Many health measurements.
Accurate and reliable measurements.
Screen with great clarity.
Easy to connect.
Improved sound during calls from the watch.
Negatives:
You can't install any apps since it's not a smartwatch.
NFC does not work for payments (due to European restrictions on Huawei).
You can't reply to any message, you only get notifications (on an Android phone you can).
It does not support emoji in message notifications.
Limited free watch faces.
Because I use it with the screen off (for longer battery life), it does not have the "tap to wake" function, you have to press a button to see the time, otherwise you activate the "raise to wake" function, which personally does not suit me.
***
And a hint for iPhone users. At first, it wouldn't get notifications at all. After a lot of searching, because although they arrive on the phone, they don't go to the watch, I found the following:
You need to go to the notification settings for each app you want to pass to the watch and change Show Preview to Always or When Unlocked. The default setting is Never.

I come from a Garmin Instinct 2 and what the GT5 Pro offers can only be matched by equivalent Garmin models at double or triple the price. Sapphire screen, titanium case and bracelet at €404. It also accepts simple 22mm straps very easily. With Garmin, you pay over €1000 for all these features and the straps are extra. The software that comes with it is miles ahead of Garmin's equivalent. The GT5 Pro is more focused on health measurements and even provides an ECG with arrhythmia detection (very important for those over 50) as well as many other health metrics. Of course, it also has training programs tailored to your age/physical condition. Also, very advanced sleep monitoring, and through the app on your phone, you can simultaneously monitor and RECORD snoring and talking in your sleep (!). You start sleep tracking and leave your phone 50 centimeters away, and it records the moments you snore or talk in your sleep, and you can listen to them in the morning (see photo). It does not record the entire duration of sleep. It combines sleep measurements with whatever the watch detects and produces very detailed reports.

For training, it has many activities and the tracking is very accurate. In fact, the running/walking path is much smoother than what Garmin provides (probably because it supports GNSS like the newer Garmin models).

The only comparative disadvantage is that it does not have GPS routing. You download an offline map of Greece to see your routes during activities, it shows points of interest but does not allow you to route a course to a specific point. However, it can display routing instructions on the watch when you install the Petal Maps app on your phone and set a destination. Then it sends the instructions to the phone, which appear as arrows, roads, etc., on a black background.

Call quality is excellent and the person you are talking to cannot tell you are speaking from a watch. The speaker is quite loud and you can hear it even when there is noise on the street or outdoors. It allows up to 10 favorite contacts, which is more than enough for most people.

I had no problems with notifications or with installing Huawei's extra software, which is very easy to do from the official website.

The first charge lasted 7 days and I still have 20% battery left, but I won't let it drop further. Charging is wireless and takes 1 hour.

Finally, I should mention that the inability for contactless payments is due to European Union restrictions and not Huawei.

Overall, very satisfied.

Update July 2025.
The new firmware version 5.1 at the end of July 25 will also add voice memos AND HRV! It seems Huawei is seriously targeting Garmin with its own ecosystem.

I have used the GT2 Pro and GT3 Active, and the GT5 Pro is a combination of these two with extra features. It has smoother scrolling in software use. If Europe allowed NFC payments, it would have no competition... For now, it’s good but not perfect; it remains a health care watch with Apple Watch Ultra quality and basic smart features, which is why it lasts at least a week on a single charge.

Its battery, with everything enabled and one hour of running per day, lasts 5 to 6 days.

Its measurements, although I have no point of comparison, are satisfactory. Anyway, smartwatches cannot satisfy or replace medical measuring devices, but they can be used as a tool for comparing daily condition under certain circumstances.

One last observation: strong hardware and smooth refresh rate, like the GT5 Pro, make it last less than the GT2 Pro, which lasted 12 days in water. We can't have it all, which is why the truly "smart" Huawei Watch 4 has a bigger battery but still lasts about the same. It would be cool if it had a solar panel like Garmin, even if it cost a bit more.

22/12

After 10 days of use, wearing it almost all day, its battery is very good... With all sensors active and doing daily running workouts using GPS, the battery will last you 6 days at most; otherwise, with moderate use (2-3 times at the gym per week with GPS or simple use), you’ll definitely get a week. In my case, from 16/12 when I charged it, with two days of running with GPS in the week, I still have 60%, using it for a total of about 4 hours at irregular intervals during the week.

Coming from an Apple Watch SE 2, which went into a bootloop (I suspect because I charged it with any charger I found, although I’ve read this happens), I would recommend charging it via PC. The charging cable it comes with is 5-9V 2A and completes charging in an hour from 10% battery when plugged into my laptop, which is 5V=5W like all PCs.

03/10/2025
After 10 months of use and several updates that changed the software appearance, the watch has remained the same in usability and battery life... What I would like Huawei to do is allow us to see images and listen to voice messages, which is only possible on Huawei phones. I’m not even talking about contactless payments; at least there you can say it’s a security issue if they can’t partner with a company in Greece... Also, from the 4GB of storage, they could at least go to 8GB; you’re paying 370 euros, for goodness’ sake... In the end, it’s a smartwatch that meets all requirements a little, with its strong point being that it’s not bulky and comfortably lasts 6 days with everything active and wearing it all day.

Purchased on 30/9/2024 from a well-known department store + gift of Huawei Freebuds 5i. Coming from the excellent Gt2 until today, I decided to make an upgrade after 3.5 years. Very good with a lot of information and with ECG, as well as measuring arterial stiffness. Now I don't know how much these two correspond to reality, but the positive thing is that they exist. The NFS does not work for the well-known reasons of Huawei's exclusion. The battery is very good, lasting about 8-9 days with 5 workouts a week and over 14 days with typical functions. Its measurements during workouts, if not the same as the Gt2, are almost the same regarding distance, speed, steps, oxygen, etc. The heart rate measurements of the Gt5 Pro are more detailed. In a treadmill measurement with the wiring of the stress test, the Gt5 Pro had +5 beats more than the medical machine. Better measurements on the gym treadmill than the Gt2, but -130 meters at about 5 kilometers (it should be noted that the measurements on the treadmill are without GPS). Of course, compared to the Gt2, which measured 650 meters on the treadmill for one kilometer, there is no comparison. It also provides us the ability after each indoor workout, such as walking (on a treadmill), to calibrate the distance at the end. That is, to manually enter the distance recorded by the treadmill into the watch, and then all the measurements of the watch are synchronized with that distance. This is one of its positives. What disappointed me, but I believe will be fixed in some update, is that although it has been set to do not disturb from 23:00 to 06:00, the screen still lights up when we move our hand. Quite good and useful for someone who exercises with a multitude of options. I hope I helped.
Update 23/11/2024 - I finally found a "solution" regarding the watch not lighting up during the night. There is a "sleep mode" that monitors sleep and various other measurements without lighting up when we move our hand, but it is manual. That is, we apply it before lying down and deactivate it in the morning. There is no convenience to set a specific time period for the watch to automatically enter this state, like in "do not disturb." Anyway... we will endure it because it is excellent in its other features. I highly recommend it.