It looks very interesting but I also think it will be an expensive piece of hardware. In an video interview someone of Samsung said that they're trying to make deals with carrier - would you buy a camera with a contract? If phone calls would be possible with this camera I could even think of replacing the phone with such kind of camera if it still fits into a pocket, but if phone calls are not possible I would prefer a wifi only version which is cheaper and without a contract. It could still get tethered to the phone. I personally expect that it will be at least 400-500$.
For me personally the SmartPhone market changes a bit. All the years ago I was up for the new phones because there was much to improve and every new release made a huge jump forward, but on the current Galaxy Nexus everything runs very smooth and I can imagine to stay another 1-2 years with it. Before I spend 500 bucks into a new Phone, just because of a slightly better camera, or into a camera like this with a phone OS inside I would rather spend it into a Micro Four Thirds camera. Actually the the Olympus E-PL is teasing me a lot - rumors say that the e-pl5 comes in few weeks with the new sony sensor from the om-d which so many love. It's has still a very nice size to always keep it with me and the M4/3 system has now very nice and affordable lenses as well (1,7/20mm from Panasonic and 1.8/45mm from Olympus). It will cost just slightly more than a new phone (or I guess this Nikon), but offer so much more. Even a little accessory to transfer the photos from the camera to the Android Phone is available.
Just my thoughts during the last weeks while I was looking at the new upcoming phones and came to the conclusion that a new phone would be a bad deal for me personally because it doesn't offer much new for it's high price.