44x33! Damn I think I would just buy a D800E and stick medium format lenses on it and spend the left over $32k on a holiday.
Phase One makes expensive digital backs. They still generally have some sort of edge (one of them is simply to be available first, Hasselblad tried here, but Phase One is stealing the show), so people buy them instead of the more economical competitors. But as far as I can understand the Sony medium format sensor is going to end up in a lot of backs, and probably Phase One's IQ250 is going to be the most expensive option. Probably still one of the most popular. Phase One's upgrade programs are also generally a lot more attractive than looking at the single unit price, so if you're already in the Phase One system you'll get a sweeter offer for sure.
Sony Exmor technology with largest pixel size so far and with MF-style bayer color filters (ie color rendition a higher priority than high ISO), I cannot think of any other result that this will be the best image quality seen so far out of a camera sensor.
Maybe we'll see Hasselblad, Leaf, Pentax, Leica all with "their own" Sony CMOS sensors within a year or so.