I checked some better benchmarks from anadtech.
http://www.anandtech.com/bench/GPU15/1248
The 780 seems to be faster. I even checked some benchmarks of 960SLI vs 780 and the 780 often wins at 1080p. The 960SLi wins sometimes. It depends on the game and how effect it is with SLI.
I'll echo the previous statement. Lateral move and loosing money. I'd hold off. The 960 can still game at 1080p for now until Pascal or Vega is released.