yeah definitely the 7970. It was released with horrid driver support so a lot of the benchmarks showed poor performance. When the 680/670 came out a lot of reviewers simply matched the 680/670 benchmarks against the original 7970 benchmarks without rerunning them using new drivers.
With Catalyst 12.7 it eats the 680 alive when overclocked.
Actually the 600 series had even worst drivers the the 7970 did at launch, I was unable to use 120hz and that terrible vsync bug and horrible stuttering. Furthermore the most ridiculous thing of all is the reviewers pitch a stock 7970 against the keplers which have an autoboost feature up to 1200mhz OC. Both cards are awesome though but the 680 needs a price drop however, if you're ever going 3D though stick to Nvidia.