Let's face it, with the iPod Apple showed you don't have to be first to market or have the best product or functionality - just have something with the cool factor. The wheel on iPods is more than a gimmick, it's actually consistently fun to use, and differntiatred them as market leaders quite quickly.
Ignoring a patent minefield - since US patents are decided by morons in favour of big business anyway ;) - Microsoft have one other barrier to overcome. No matter how well they implement the different uses here, it will initially launch as a pricey gimmick as it'll only be high end hospitality. It will have to both really take off, AND drop in price before they stand a chance of hoem users picking up, or else it'll do a PS3.
One last point, is anyoen else wondering about the "barcode"? Let's say my table detects a credit card sized shape and searches for an RFID chip. Is this secure, or will MS try to push a new secured standard for both cards and for portable devices?
All in all, it's risky, but it's got a wow factor that will draw non techy types away from noticing what a POP (pile of poo) their flagship desktop OS is, which has to be good for their shares.