For me, honestly, most driver issues are........ user error.
Most Nvidia users who move to AMD then slate the drivers do so because they are more used to forcing one method of doing something, don't bother looking around the control panel and don't realise that a decade of using Nvidia means they are used to loading up program X, Y or Z to do all their overclocking, game tweaking, fixing refresh rates(pretty much a thing of the past though), forcing trip buffering and not realise that, and vsync are only opengl options in the control panel, etc.
What you've gotten used to over a decade and forget you even do doesn't make another product you aren't used to bad, simply different.
Its been since a 8800gtx that I've had an Nvidia card(of any substance I actually use on a frequent basis, got laptop Nvidia gpu's), so when I next have one(if ever) I simply won't be used to the control panel, I won't automatically know that forcing options x,y and z works in very few games and often in most new games will cause bugs and texture glitches and I WON'T instantly decide the drivers are crap.
I know through experience that forcing anything but AF to max, vsync, trip buffering(and using a 3rd party program to do those two for dx games), and forcing anything but standard AA methods will be FAR more likely to cause issues with new games, flickering or buggyness, especially with the increasing number of games that don't actually have AA as standard anymore.
If I leave 16xaa, vsync off(better done ingame often, just cause 2 sucks on both Nvidia and ATi with vsync on, its laggy as crap, its smoother by far when not vsynced) and box AA and I literally never have game issues, well haven't in as long as I can remember now.
I'm also completely used to having my own profiles for clock speeds in various situations and takes a minute to sort out when I first install windows as usually profiles stay working fine with a driver reinstall.
These little things tend to be missing, and its literally just EXPERIENCE with how the drivers work. I wouldn't know if forcing 8x Aa with some fancy mode often causes issues with new unoptimised games, because I'm not used to the drivers, nor would I be used to dealing with clock speeds that aren't detecting full 3d in certain games, windowed, maybe with aero on or aero off, or in various other situations.
People too often confuse lack of experience or complete familiarity with one driver style, with a driver being crap.
People also lack some basic common sense, AMD have several driver teams, the guys working on this months release will move on after to work on probably a release in 3 more months, with a team working on a feature for next months and a separate team working on the driver for in 2 months time. Thats how software works, Nvidia take just as long to fix problems, its just in one driver set instead of 3, its still only one release since a problem picked up.
Also 98% of AMD's driver issues, most users don't have, and are almost all fixable with clock speed fixes, IE powerplay causing issues, and remember the grey screen problem only happened AFTER a powersaving Windows update that changed how powerstates were recognised marginally, you stick your clock speeds to full 3d(especially with dual monitors, something Nvidia has to do by default now) then ALL these issues dissappear, this has been a widely available and known fix since a day after the 5870 launch and STILL people can't fix something incredibly simple themselves, not a perfect world, but thats life, its not even a "fix" to me, its just in my list of standard things I do when I install windows now, again, experience trumps most driver issues.
ANyway, AMD seems to have another huge win over Nvidia in the coming weeks/months, Apple to take on their Apple TV with an AMD gpu AND CPU, which is immense. Apple using an AMD cpu only strengthens the ties between the companies and only makes it ever more likely Apple will push Nvidia even further out in the future.