Is it worth going to a GTX 970 from my 660 SLI setup?

I am getting tired of games not supporting a SLI config rendering my second card useless. Is it worth going to a 970? I can't find any benchmarks comparing the 2 against each other to make a good decision. I don't want to make a lateral move though, I am hoping for better performance even in games that utilize the SLI setup. Any input would be greatly appreciated.

In terms of heat and power consumption the 970 clearly takes it all.

I know for sure that 2x 760 passes 780 and with OC even the 780ti; the 970 slightly passes the 780 and the 780ti so I wouldn't say in terms of performance you'll gain much improvement.

If anything sell your 2x 660 and get 980.

One really good newer card is better than two older ones, as predator said selling both you 660 and buying a 980 would be best bet. The 660 doesent go cheap either you might not even be out of pocket if your patient selling your 660 cards.

@PredatorRules: Thanks for the input. Is the 980 worth the extra cost over the 970 though? I currently game @1080p and don't see myself changing that anytime soon.

Unless you plan to SLI 970s yes the 980 is better GPU.

EDIT: doens't matter on what resolution you play, it's for future proofing max settings, but it's basically depends on you, on how frequently you change GPUs.