I don't understand why some of you are so disappointed. It's not revolutionary on a 8800GTX level, but it's still a damn fine card and a big step in the right direction regarding GPGPU performance.
I think most are comparing the performance of the 7970 to the GTX 580 1.5gb after rebates price. If you compare it to the GTX 580 3gb then the $549 SRP seems about correct vs performance with a deduction for the somewhat questionable nvidia only features. Give the driver team a couple of months or less and I'd think the performance gap will only increase. I can't see nvidia being able to squeeze much more out of the 580 other than optimization for newer games.
With the 7970 nipping at the heals of the 6990 and 590 it makes me wonder what kinda beast the 7990 is gonna be.