I've said it before but really a Sony-Nintendo alliance would be highly beneficial to both companies, especially if Sony could convince Nintendo to work together on game-centric phone/tablet devices. A Sony-Nintendo line of "gamer phone/tablets" IMO would be reasonably successful.
But aside from that, why buy a Sony phone over an Apple or Samsung or LG or Motorola or Nokia/Windows? There's just too many companies making basically the same product.