And even if you ask a AMD user, he'll too tell you that Nvidia has better drivers.
If you put a gun to my head and made me pick which one was better, I'd say Nvidia, but it's been really, really close this past round/year. For single card, I think AMD has been slightly better this round than Nvidia. But Nvidia continues to be a bit better for multi-GPU configs.
At this point in time, though, the difference is negligible. It's definitely not been true that driver support is a reason to go Nvidia this round.