I would say that the HD7970 and GTX680 are almost at the same level looking overall... - there are things where one is stronger then other things where the other one is performing better...
The main question you have to ask yourself is for what are you gonna use the graphics card for? For general everyday usage, you won't see too much difference... if you're gaming, double-check your games is specific forums for which card/driver is the best... also, how many and how big monitors are you gonna use?