i'm in the position to switch from my actul video card nvidia geforce4 mx 64mb to an ati 9100 128mb.
When I "upgraded" my system I got a ATI 9100. For my old NVidia card I used binary rpms from livna that just worked. I still have not got the ATI card to work. Although there is an rpm in livna testing.
From my experience, ATI is more talk than reality in their linux drivers. My hope is that when I upgrade to FC3 the new xorg drivers will work.