Here's a small snippet from their conclusion:
It may seem like my testing with gaming performance in Vista all resulted in a feeling of doom (nope, no OpenGL support!) and gloom, but don't let that scare you off just yet. I think we all expected there to be some initial growing pains with the Vista operating system and PC gaming simply because of the dramatic shift in driver technology that had to take place; I just don't think we expected it to be this bad. AMD's driver development team is definitely a leap ahead of NVIDIA's as the initial release ATI Catalyst driver offered a gaming experience much closer to that of Windows XP in the new Vista OS than NVIDIA's initial Forceware release. This may change as driver revisions are updated through the comings months, so we'll definitely be keeping an eye on both companies progress.