True, you can get an factory OCed 670 which costs less and is not much slower than the 7970GHz edition nor the 680 but we are not talking about that.
What we are talking about is which is the best card at around the $500 mark and i simply can't agree that it's the 7970 GHz which is just an OCed version of the normal 7970, not when you can get a Factory OCed GTX 680 at around the same price, with better performance and less noise/temperature levels. It's simple logic actually, nothing more, nothing less.
Guides For GPU Power Users
(Sometimes its Good to pay tribute to some people instead of copy pasting their guides.)