Sony: Why Vita gives us an advantage over Wii U

[Conegamer]

The big difference is that most, if not all, of the WiiU games will integrate the tablet controller, or the "GamePad", whilst very few Vita/PS3 games will do this.

Also, it's down to cost. The PS3 new costs around £180, the Vita £230, and the WiiU will cost somewhere between the two, probably.