How good are the Ati graphics drivers?

Hello, I am going to buy a new graphics card for my computer. Now I have to decide between Nvidia and Ati. I know, the Nvidia drivers are good, but with Ati I have no experience at all. How easy are the drivers to handle, how stable are they, and how fast (perhaps also in comparison to Win). Perhaps there is someone who made direct comparison between Ati and Nvidia cards under Linux. Or does anyone know a site to find meassured benchmarks under linux of all recent graphics boards? Thank you, Johannes -- Sieht gut aus...schade und ich hatte noch so viele gute Ideen! Don't summon anything bigger than your head!