It's consistently twice as powerful as 6970, so yeah, it leaves 6970 to eat the dust. It ought to run any game at max settings (provided the game itself doesn't have issues not related to video cards, which Last Light might have).
GTX 770 is apparently a factory tweaked GTX 680 with just a little more power.
My info is from Guru3D. Obviously you should check it or your preferred site before jumping to conclusions based only on what I said. Not to mention it's quite an expensive card, yet still not from the upcoming generation technology wise.