Don't have any driver problem with either ATI and Nvidia stuff. (I am running both)
8500DV with MSI KT3 Ultra
7500 With AMD 760
Before that was running, Rage 128, Radeon 32MB LE, Radeon VIVO all without any problems.
(also never had any problems with TNT, TNT2 Ultra, GF3 Ti200)
Initially I noticed signficant slow donw when I put in the 8500DV. Was getting 2000 in 3DSysmark 2001. After updating the Via 4 in 1 driver, the score went up to 7000+. (with latest VIA driver & Cat 3.1 I get about 8000, the card is clocked lower than regular 8500, I believe it's 230/230) And real game performance improved by quite a bit too.
Currently running Cat 3.1 with no problems.