They tend to abandon???
The Mate 9 was one of the first phones with Android 8.0 Oreo AND they even added Project Treble support to allow for easier updates. Ask me if LG did the same for their flagship phones!
I've had a Mate 9 and now a P20 Pro.
only issues for me have been that ATT doesn't allow VOLTE (HD Voice) on BYOD phones. (T-Mobile doesn't have that problem.
Updates have been good with at least security updates every 3 months or so.
There are some small issues(quirks really) that can be a little annoying. Their power management is really aggressive and sometimes stops apps from functioning properly. You have to go into settings and exclude specific apps from power management.
Settings aren't really set up like typical Android so finding things sometimes is a bit difficult.
UI is extra smooth, just as smooth as iOS, fastest fingerprint sensors I've used, cameras are great, and except for the political issues Huawei is having great phones all around.