Witch psu too choose for 660 sli..

The EVGA NEXB 750 is a decent power supply, but with the choice between it and an Antec or XFX, yeah, not the EVGA. The Antec HCG750 would be my vote, as you'll be right in the middle of the power supply's peak efficiency when you're gaming. This will help prolong the like of the power supply, and keep it cooler as well.