There are many reasons to dislike Nvidia on Linux. Here is a little thing that bugs me all the time, the updates. Normally the system updates would be quick and fast, but with the proprietary drivers of Nvidia involved, it gets quiet slow process. And I am not even talking about any other problem I encounter, just about the updates.
As an Archlinux based system user (EndeavourOS to be precise), I get new Kernel updates all the time. That means every time a new Kernel version is installed, the Nvidia driver DKMS has to be installed too. And that is basically the slowest part. But that's not too bad, even though it's doing this twice for each Kernel I have once.
What's more infuriating is, if you also happen to use Flatpaks for a very few applications. I really don't have many Flatpaks at all. Yet, the Nvidia drivers are installed in 7 versions or what?! And they are full downloads, each 340 MB or more. This takes ages and is the only part that takes long to update Flatpak system. I always do flatpak remove --unused to make sure nothing useless is present. /RANT (EDIT: Just typos corrected.)
And in addition to that, it's the only thing that breaks on my system that isn't my fault.
My next GPU will definitely be AMD unless Intel catches up very quickly.
My embedded AMD GPU has been unusable under Ubuntu. Constant crashes/freezes. When trying to find a workaround (unsuccessfully), I found lots of other people with slight variations of the same problem - same symptoms, but different root causes... seems like at any time there are several system-breaking bugs and every time one is removed another is introduced. You just have to hope your kernel happens to be one that happens to work with your specific config.
My next platform will be Intel-based.
AMD works fine for me. I had a Thinkpad P14s for a while and my gaming computer uses a 6800 XT.
Same - Thinkpad X395 (R5 3500U) for casual use, RX 6750 XT for gaming, FirePro W4100 for work, and zero thinking about GPU drivers between the three.