It is in the words of many, "good enough". Its fast and easy, and finally tethering is decent. These are guys that can buy ANY camera. But, the easy autofocus and ease of use and speed just trumps the phase stuff and NO AD questions which camera these people use. People that shoot both will tell you the Phase file is better ,and it is, but too many people IQ doesn't outweigh the systems detractions.
You've got many camps here -- you've got the MTF Chart Guys, and the Theory Guys, and the Chip Design Guys, and the Commercial Photographers and the Landscape Photographers. Everybody's invested in some way. The MTF guys I'm sure are loving the IDEA of this camera, but like Anton asks, "How many will actually write a check?". And for the pros, most of them rent anyway, so how many of them are going to write the check? So who does that leave -- Lars The Broker, in Austria, and Antonio The Coke Dealer, in Milan?
When I look at my Phase files at 100%, clearly they are superior to the 1ds3 or 5D2, but at arm's length, (the way 99% of people look at a photograph), the Canon files appear sharper because there is more inherent depth of focus, due to the smaller chip. Try it yourself -- set up a scene and shoot the MF and 35 and see which FEELS sharper when you're holding a 17x22 print in your hands, (at normal viewing distance; not Electron Microscope distance).
Also, what good is 50MP if you're light is dying, and you've got to drop to a 30th, and the mirror slap kills all 50MP of sharpness? Whereas, with the Nikon/Canon, you don't bat an eye at running the ASA on up to 800, to keep a safe shutter speed.
And my true feeling is, the 1ds3/5d2 file is more than just "good enough". It's simply a damn fine file, especially if you're shooting for money, which means either RGB at 72, or CMYK at 300. Work for hours, retouching a picture that's got a lot of blue in it, whether it's from Phase, Sinar, Leaf, Canon or Nikon, and then SoftProof it in CMYK -- it is The Great Equalizer. All those tens of thousands of dollars spent for 16 bit Medium Format, and it all washes down the drain when you convert to CMYK. So I ask you, Why spend the money...?