ATi Catalyst

Do any of you guys use the catalyst driver from ATi? Is it worth installing? Is there a significant performance difference from installing it and not installing it?

I have a:
3.6 P4 w/ HT
2x512 DDR 400
ATi Radeon X300

Would I notice an increase in performace (more fps in games) if I install it?

I installed it because it gives me very slightly better graphics and a wider selection of resolutions in some cases