After the Samsung Gear S3 Frontier, which I was never satisfied with (1-day battery, GPS that didn't catch), I ended up with this.

I've been a owner for about 2 months:

+ The watch measures many things and (I believe) accurately
+ GPS location is "spot on"
+ User-friendly menus. Many options and watch faces
+ Battery depending on usage, 4-7 days,
+ It hasn't noticed any hits. I did put a screen protector on it. But the body feels nothing.
+ Screen with excellent brightness, night and day
+ Relatively loud beeper and very good adjustable vibration
+ Relatively large screen but not huge. (I have presbyopia, the size is quite satisfactory)
+ Amazfit responds to emails and relatively quickly
+ Very easy mobile app

- I found it slightly lacking in accuracy. With many tests regarding the sensitivity of automatic activity recognition, when I'm on the bike, it thinks I'm cycling.
(With the Samsung, I never had this specific problem).
So I disabled cycling from the automatic activity recognition.
- It doesn't have a speaker/microphone but you probably can't have both use in the sea and a microphone. So you can't make a call with speakerphone.
- It doesn't have NFC (personally, I don't care)

As another user mentioned:
> I hope to find straps from abroad (along with a small screwdriver)
> I don't know about service. I'm more worried about the battery life.
> Theoretically, it is waterproof and in seawater. The truth is I will avoid it. If I can't resist, at least I will rinse it afterwards with fresh water, as I've read I should.

Additionally:
> Heavy, you feel it when you wear it. You don't search for it. This isn't necessarily a bad thing.
> I haven't yet found if and how I can keep it connected to the mobile but also with BT handsfree and be able to see the call on the watch but talk from the handsfree...
I will ask the company about this...

Finally, I don't know how it compares to the new Trex 3. Probably the Trex 3 will excel at least in price, since I got the Ultra for 380.

I will return in the future with an updated review.

I bought it in 6/2023, I wear it 24/7 and overall I am very satisfied with its use.
POSITIVES:
+ Stainless steel case.
+ Battery life of over 2 weeks with training mode every 3 days.
- Suitable for swimming, even has a DEPTH METER for light dives.
+ Very durable against impacts. It has no scratches despite accidental bumps on doors/handles, etc.
+ Regular updates and countless watch faces so you don't get bored.
NEGATIVES:
- Service??? I need a repairman here..., straps???
- No microphone/speaker, only notification and call rejection.
- Does not support NFC payments.