http://techreport.com/articles.x/22653/8
http://techreport.com/articles.x/22653/9 (example of gtx680 stuttering more, though to be fair the way TR measure stuttering may not reflect real life due to the rest of the graphics chain)
http://techreport.com/articles.x/22653/10
http://techreport.com/articles.x/22653/11
Looking at sub-50ms stutter metrics and framerate numbers, even stock vs stock the 7970 holds up okay against the gtx 680 and the 7970 has more overclocking headroom on average. When both are oc/ov'd to the hilt, they are on par with each other though the 7970 will have more power/noise/heat.
The bottom line is that the gtx 680 is not noticeably faster or smoother than the 7970 when averaged across lots of games (anything less than a ~15% difference is difficult to notice unless you're already in the unplayable fps range) and has 1GB less VRAM, no ZeroCore Power feature, and apparently lack of voltage control for reference cards. Where the GTX 680 does better is feature set, with CUDA, PHYSX, SLI (smoother than CF right now, from what I hear), adaptive VSYNC, adapterless Surround, GPUBoost, and power efficiency with the noise/heat benefits that entails (at least at load). Is it worth $50 extra (or more than $50 if you consider the Three for Free games that AMD is bundling with the 79xx series starting in May?). Only you can answer that question for yourself. For me I needed more compute functionality, but if I just wanted to play games, I would rather get a Kepler, probably the lower-priced GTX 670 though since I feel that the GTX 680 is overpriced right now.
I don't either. People tend to play games that are fun the most. TF2 and L4D2 on triplescreen are more fun for me than games like BF3. I bet people play Diablo3 and Starcraft II way more than BF3, on a daily total hours basis. And believe it or not, Counterstrike 1.6 and Source are still insanely popular despite the aged graphics. Of course the posterboy for popularity-despite-graphics is probably Minecraft. I still haven't played that and don't intend to, but not for graphics reasons.