Save your money and get a GT300 next year if you really use it mainly for Linux and not only part time.
While Kano is rightly hinting that nvidia's binary drivers are in some ways more mature than fglrx, waiting for an unreleased piece of hardware would be a waste of time. All public knowledge about the GT300 is based on nvidia's press releases, and those releases contain obvious lies. It seems that their promises are mostly a marketing move to stall buyers until nvidia's next generation cards are finally ready. Whether they can actually deliver (and if, when) must at this point be considered "unknown".
But the release docs say:
and if that didn't work, you'd have seen a lot of complaints in here.ATI Radeon™ HD 5800 Series
Ugh, my new GTX260 got sent back for repair 5 weeks ago and it's increasingly unlikely that I'll ever see it again. Here in Australia the GTXs are clean out of stock, and even the 5850s are as rare as hen's teeth due to demand.
I really want to stick with NVIDIA but without even a ship date for the 300, I think I and a lot of other Linux users will end up resorting to a 5850.
I really liked my GTX260. When it wasn't crashing (hardware fault) I was able to run Far Cry 2 and Oblivion at 1920x1080 with medium settings at around 20-30fps in Wine. I do hope the Catalyst drivers are sufficiently mature enough to do something similar.
I thought ATI was making massive strides in Linux support and that new card users (4000, 5000 series) would have Nvidia-like performance in most cases, with modern drivers?
as fglrx shares a lot of code with the windows drivers, 3D performance on linux is close to 3D performance on windows. IIRC fglrx doesn't implement EXA though, resulting in slower performance on certain 2D operations.
The OS drivers are different: they offer good 2D acceleration, but the 3D code isn't as optimized as the windows drivers (and in some parts still unfinished). OS drivers aren't written until the hardware is actually released, so it takes a while until they're available for recent hardware.
On openSUSE with a radeon hd 5850, Kwin crashe automaticaly... No driver work for this gc ??