The drivers are getting better after amd bought ati, but there's sadly not aiglx support. So it's a pain in the a** to get it up and running.

It looks like they devoted most of their resources to the vista drivers for now. It would have be better for them to open up the drivers, and they would have beaten nvidia in a short time. And more computer users with ati cards would consider switching to linux. And nvidia would likely open their drivers too, so they would not loose a lot of costumers.