Amazfit Watch faces

Hello. I'm going to spend some money on smartwatch. I'm thinking about two, one is Xiaomi Amazfit GTR 2E. Yeah, it is Xiaomi, who can tell why they pretend it is not? But in subject, what are your experience with GPS and oximeter?

I saw some maps with walk or cycle tracks, and sometimes route was very strange, for example through buildings.

And second, oximeter .Does it work at all? In any review on the net anyone talking that it not working, in one men showed value 89 - according to the measurement he was dying, but in fact was okey.

Is it multithreading like full feature version GTR 2? Are watchfaces for GTR and GTR 2 compatible?

I upgraded from Mi Band 5 to GTR-2e.

I find the HR sensor of GTR-2e very reliable and steady during workout or idle time. I don't expect it to capture sudden spikes, after all it only measures HR at 1-minute intervals. I have compared it several times with the HR on my OMRON blood pressure device. The different is negligible. Also, since the first day I bought the 2e, I don't see any sudden drop on the HR graphs which might indicate detection failures. I ran on a treadmill 13km/day x 5 days/week. I don't see any problem with the HR reporting.

I am very impressed with its battery life. With extensive indoor exercises, the watch can easily last for 14~17 days per charge cycle. Much better than my earlier expectation of 7~10 days.

I find GTR-2e a very good watch.

GTR2e is the best watch for money .. the only bad thing about it is the GPS .. if only they can give us the option to manually update AGPS data

edit: forgot to say , i didnt try any GTR/S 3 watches