In my opinion, it's best not to be hasty when building a pc. If the deal ends, then they'll probably have another great deal that might be better.
Also, at that price level. Why not a ASRock z77 Extreme 4 or Gigabyte D3H (this one can't use cards @ 3.0 x 16)? Personally I'd get the Extreme 4 if I was gonna use 2 GPUs or the Gigabyte for 1 GPU.