I have recently switched from an NVIDIA Quadro card to an AMD FirePro card. I use GNOME/Wayland and the difference is quite big, with NVIDIA on nouveau, there was regularly flickering (at random moments), artifacts and other problems. The FirePro with the amdgpu driver on the other hand works completely flawless on my machine.
[1] https://www.phoronix.com/scan.php?page=news_item&px=XDC2016-...
nouveau was always pretty awful, but the nvidia binary drivers always Just Worked, across many models for many years, whereas with AMD it's always been a crapshoot whether a given card would work properly or not.
The binary drivers always kept up with the important things (indeed they were well ahead of AMD in terms of doing accelerated video decoding on linux via Xvmc and later vaapi, their xinerama integration was always better...). Sure, they don't support Wayland, but that's a solution in search of a problem; if and when there's actual value to be had by using it I have confidence that nvidia will support it.
X is also insecure from the ground up, that alone is enough incentive to move away from it.
Not
- if you don't want any GUI application to be able to read keystrokes/mouse events/screen grabs of any other GUI application,
- if you want per-display scaling factors,
- if you want a tear-free desktop experience.
If AMD is worse, they're failing to clear a pretty low bar.
The one chink recently was the new display code, which was a requirement for Vega (but not for earlier generations), and which was a genuine open sourcing of an existing, Windows-focused code base. That process took longer than one might hope for, but we're clearly over the hump now with it going upstream.