[quote]I’ve never actually seen or felt a bug in an OpenGL game though with my Radeon.
[/quote]
Well, watching a finished OpenGL game is another thing than developing an OpenGL game and ecounter driver problems. 
A finished game usually includes workarounds for known problems with certain drivers, OS’es, etc.
When you’re developing a game you’re supposed to find all these workarounds. 
Most commercial (C++) OpenGL games use a sort of ID’s OpenGL engine. So if these engines have nice ATI bug workarounds (render paths… :-), all the games will benefit. Carmack stated during his Doom3 development that Nvidia’s OpenGL drivers have got gold status for him (what’s concerning OpenGL spec conformity), but no other drivers.
About Java OpenGL games:
° Alienflux uses hacks/workarounds for ATI driver bugs.
° In former times Agent9’s game didn’t run on my ATI PC at all. On a Nvidia PC it did.
° Some time ago Wurm-Online produced BSoDs on my ATI PC while it run perfectly on a Nvidia PC.
° My own little OpenGL 2d game can’t use some very nice official OpenGL extensions (related to 2d texture sprite stuff) because they run on Nvidia but not on ATI. 
° Please scan the forum to see how long it took JOGL to run in a solid way on most ATI cards. And it’s “just” an OpenGL binding, so if OpenGL is OpenGL why does the same binding run perfectly on Nvidia but not on ATI?
ATI’s desktop OpenGL drivers today are much better than a few years ago. Their mobile 3d card drivers still deliver many OpenGL problems, though.