Can you test GPS a bit, see if they fixed accuracy? I've tested 8.2.1 vs 8.1.6.0 and on same position accuracy on android N was 6m and on android M was 3m, almost double difference.
latest china is Version: V8.0.4.0.LHOCNDG (MIUI8) .
Changelog:
System
Fix - Battery optimizations (10-09)
Lockscreen, Status Bar, Notification Bar
Fix - Time wasn't displayed in thecorner of the screen (09-26)
Fix - The phone didn't go to sleep modewhen the screen was locked (09-26)
Fix -...
To answer myself:
I've used it to migrate redmi note 2 to Mi5 and it worked better than I've expected. All settings, homescreen, files, apps were migrated as expected with no hassle.
:)