I have an ATI Radeon 7000 and it screams.
After I upgraded to OSX 10.1.5 it did get an update from ATI, but has worked ver well.
I have a S900 the US version of the Pulsar. I also popped a Sonnet G3/500 into it and 400MB of ram and three SCSI drives, all Seagate Barracudas.
I has ran everyday since 1995 and is now networked to my new Intel Imac which mounts all the SCSI's wihtout a hitch.
Go for a ATI Radeon.