Black Ops 2 Launch Guide (Wii U 720p 60fps, 360/ps3 SUB-HD)

[VGKing]

Eurogamer has the comparisons up, looks like the Wii U runs at the same resolution as 360.
Here's how it goes:

Graphics: XBox 360 > Wii U > PS3
Performance(frame rate): Xbox 360 > PS3 > Wii U

Of course the 360 version wins in each category since it is the lead platform for the game.