500 series was blown out of the water by the HD6000 series in price/performance, while the 600 series is hugely expensive compared to the 7000 series.(See: 7970s at ~$450 and 680s at ~$550 for the same performance, with the 7970 having a larger overhead for OCing) Driver wise, for daily use I've found Nvidia's drivers giving me a lot more hassle than AMD's, although you need third party programs to do application-specific video configs.
So far as I recall, only through the hit or miss unlocking of 6850's into 6870's did ATI beat nvidia in price/performance. And with the advent of the quite affordable factory overclocked 560ti's, that advantage has been gone for awhile. And quite frankly, I have several Nvidia based rigs (8600gt, 9500gt, ion, 335m, 460m, 560m, 560ti, quadro 6000), and I've never, ever had driver issues, even with beta drivers. The ati systems I have dealt with (e-350 apu, 4610, 5870m and some old x1600) have been fraught with issues. The e-350's were pretty painless, but I never could get the 4610 to take a driver update without fritzing out and crashing. And the 5870 in the g73, well, 11 restarts, 2 BSODs and more than a few non fatal crashes was all it took to update drivers successfully. Which actually decreased render performance in solidworks, all said and done. Never did get the 4610 working; just replaced with an old 8600gt, which dropped in and worked fine.
For overclocking, I can honestly say I've never tried overclocking an ati chip, since its enough of a pain in the ass to get the things run normally. My 560ti has been nothing but a pleasure to overclock. Sitting happy at 975mhz since november with no trouble. And a 4xsli gtx 680 rig just took the performance crown in the 3dmark 11 hall of fame.
For current pricing, yeah, nvidia is more expensive, because they cant keep up with production. The 7970 has a $50 higher msrp, so when nvidia gets production ramped up, the ati is gonna cost more.
All said and done, I firmly believe nvidia to be better. I suppose when 80% of your experience with a company has been a complete pain in your ass, you tend to dislike their product. Stack on that all of nvidia's goodies, like physx, cuda, and better 3d support, and it pretty much follows that Nvidia is better.
Current trends place us at *incoherent male orgasm screaming* by late 2013