Well you are comparing Ghz cards against a 680 card. The Vapor-X from Sapphire is the strongest card on the list of cards that you have listed and would be one of the top 1 or 2 cards in the single GPU market. The 680 without a overclock is in line with a 7970 non ghz but the ghz edition is ahead of everything at the moment. So plus one for the Vapor-X. Why because you get superior cooling then the other solutions, you get superior components on your card that you wouldn't get on other cards the caps, mosfets, and chokes.
I wouldn't do the HIS, preferring to stick w/ major brands. As to which one to buy, it may depend on what games ya play..... I'd go thru some of the reviews, look at how each oine does in each game and make a decision thereafter.
It certainly does matter what you play if you are someone that plays games with Physx then you may enjoy the 680 more but on straight merit of raw performance the 7970 ghz will win 10/10 against a 680.