Nvidia over ATI: Choosing a video card [duplicate]
Solution 1:
Currently the AMD drivers are more open to linux development. But before this Nvidia was way more stable for linux and AMD had the most issues. So AMD still has some catching up to do. I would say for now nvidia is still best to go with. The most driver issues that I've experienced with nvidia was lately with optimus technology on newer laptops. The bumblebee project is doing a teriffic job at battling that however. It's a matter of adding a ppa or two, installing via apt-get and you're good to go.
It's your call. But even if you're not afraid to get your hands dirty I would not urge for AMD, because there's always something to do for the nvidia cards too to keep things running nice and smooth. If you want the least possible hastle it's a no brainer, nvidia. Reasons being: 1) they're still ahead when it comes to driver stability. 2) nvidia used to be more stable and so it has a much larger comunity behind it to counter linux problems with nvidia cards.
Solution 2:
It does seem like nvidia has a reputation for better linux compatibility than ATI. However I believe this is less true today than it was in the past. Also, if you're considering doing any bitcoin mining (a stretch, I know) ATI cards will do it faster.
Solution 3:
I have both, and they both work fine.
Bonuses with ATI -
Better opencl performance
Cheaper for more stream processing units
More development in the open drivers
Bonuses with nvidia -
They have a mature freebsd binary driver(probably not relevant for you)
Generally more stable for the time being
If you dual boot, they have less issues with windows gaming if you have a multi-gpu card