I installed a Radeon VII yesterday (replacing a 1080Ti) and this has been my experience:
1) Resolve 15 - garbled BRAW in the viewer
2) Updated to newest GPU drivers (as far as I can tell - this was at 1am

) - still garbled
3) Updated to Resolve 16 - BRAW playback fixed and flawless
4) Next checked some 50fps h264 clips - noticeably worse playback than on the 1080Ti, heavy stutter even with no grading
5) Updated to Resolve 16.1b3 - 50fps h264 playback back to normal when grade is off, slightly worse playback than on the 1080Ti when grade is on (although tbh in both cases it wasn't really playable).
With all these updates almost everything seems to be working fine, with one small exception - when I first open Resolve it seems to take a while for the viewer to display any video. Not sure if anyone else has encountered the same issue?
Everything else seems to be fine, including BRAW, and one test export I did last night was ~16% faster than on the 1080Ti. This was a mixture of 4K ProRes LT and 4K BRAW Q5, both with temporal and spatial noise reduction as well as several pretty basic color nodes.