At the end of writing this post, I've just gotten more confused as to whether the AMD driver stack is as good as Nvidia or worse or better really. :x
There was a time when ATI/AMD drivers would often be lacking on a new game release and had legacy bugs like long standing issues with hardware accelerated 2D surface, missing functionality for less mainstream texture formats which the driver exposed in capibilities but didn't actually do anything, etc. - this has not been the case for a few years now.
nVidia have had more ropey drivers of late but there has been a key difference in that when their drivers have a problem there is almost always a slightly older driver that works, etc. with AMD that often wasn't the case.