A GTX 680 would be the equivalent, the biggest known driver issue with the 7970 that wasn't it acting oddly in one particular game was when 2 displays were plugged in the drivers would crash and cause a blue screen when the card wasn't doing much like web browsing, but was fine with games. Since 12.7 they have fixed that.
Xfire adds issues as well and unless your playing above 1920x1080 then its really not needed. With an overclocked card I can max every game I own shy of metro 2033 without the frame rate dropping below 60fps and even in metro its only a minor drop from time to time.
That being said a 670 can do that as well or maybe not quite as well but damn close. Is the 7970 worth the extra cost? One other thing to note if your going with a cheaper card like a reference design one the 7970 isn't all that quiet either once that fan gets going.