I think youre in for a surprise if you try the new drivers! On ubuntu the install is seamless, even otherwise the installer just works and ati has pretty simple interface for doing colour balancing of multiple displays.
Let me disagree with that. The open drivers don't support 3D, and the closed drivers make X crash at least once a day on my setup and similar ones. I have a laptop that is just one year old. All in all, I always got a better Linux experience with NVidia.
The open drivers do support 3D. You won't get the same performance as the closed drivers, but you will get accelerated 3D plenty good enough for desktop effects and simple 3d games.
Are you using some funky compiz plugins ? What distro are you using ? When did you last update your drivers ? What laptop are you using and what card does it have ?