So far, dx11 cards really haven't impressed me at all.... If it were me in your situation, I would continue to run the 285's until something better comes out. Going from dx10.1 to 11 isn't as big of a jump as dx9-10, or at least to me. Ati cards have borked drivers afa xfire is concerned, and nV cards in your case will set your house on fire..
With the newer games out lacking imo, might as well stick to dx10.1 and continue ripping up COD mods. the 6k series and 2nd gen fermi gpu's hopefully change my mind.
