They all support DX 11.1. I'd go for the HD7950 as well, out of those 3. Just bought a Sapphire Vapor X HD7950 myself.
Ah ok, I've only found a few that actually list it as supported on Newegg so I didn't know that.
I'm leaning towards the GIGABYTE GV-R795WF3-3GD
on sales for $299 but I just can't decide if want to spend that much with a new gen of cards coming out in about 3 4 months. Especially when the HD 7870 and GTX 660 Ti seem good enough for as much as $80 less. Just don't know which way to go.....
Edit: all this talk of frame latency vs FPS is throwing monkey wrench in the works as well for my decision making....