I'd skip this driver for the simple reason that the same day we saw this WHQL driver, the Catalyst 12.7 Beta hit us and from our original testing with the HD 7970 GHz Edition, we're really happy with what's going on with that driver.
It also seems the 12.7 Beta is one that AMD are going to focus on when it comes to performance which is something that we haven't seen in a while. Of course later this month when the official WHQL hits us we'll check out the Catalyst 12.7 driver. For now, though, we'd recommend you hit up that Beta driver over this WHQL one.
On the specifics of this driver performance, it is a little all over the place. At times we see a nice little bump other times we can see a decent dip in performance. For the most part, though, we see that there's really no change between this 12.6 driver and the 12.4 WHQL driver.
The next few months are going to be important for AMD. The 12.7 driver is going to be important as it should focus more on the performance side of things and AMD need to release the Dual GPU HD 7990 that is hopefully not too far away.
For now, though, you can probably skip this driver and go for the 12.7 Beta.