I'm running a Radeon RX560 (replaced an Nvidia card), using the open source AMDGPU kernel driver and Mesa. It's seamless and works at least equal to (probably better than) the proprietary Nvidia drivers.
I went with Radeon as well because their open source drivers. I am a very happy user. No more bad surprises when updating kernel, which has saved me more time than I'd like to admit, since I used Nvidia because of performance.