I got a 680 for $500 right when it came out, and I like it. But the 670 is only 5% slower, that is amazing! Also the 670 is $100 cheaper. I feel like nvidia did an amazing job with the 670. The 7970s (which can over clock higher) IMHO will drop a little in price and EVERYONE will win. The 670s are still in stock at newegg almost two hours later. AMD and NVIDIA did a great job.
BUT, I feel like NVIDIA overcharged for the reference 680. I think with this new architecture they weren't quite sure how much of a performance hit the cards would take with one SMX cluster disabled. It was reported that TSMC was having problems with the 28mm process, so the 680s are ones that are fully functioning and the 670s are 680 chips that didn't quite make it. Like a 560ti to a 560ti-448 core, except that the price/performance gap was greater (when the 448 came out).
I feel like the 680 should've always had 4GB of memory and better components (I know there is always a risk when adopting new tech). I know NVIDIA has refunded money back to customers in the past, do you think this situation warrants a refund?
Either way PRICE WARS
EDIT: The 670s are still in stock 3 hours after launch