http://www.eurogamer.net/articles/digitalfoundry-mass-effect-3-wii-u-face-off
According to this face-off, the 360 version is the best out of the three consoles; with Wii U coming second in performance and PS3 taking last spot.
This quote in comments really got me thinking:
"The thing is that I just feel like Nintendo could easily have spent another couple of dollars to make the console *just* powerful enough to be obviously superior to the other two. If they had done that, they would have changed the whole coversation around the WiiU, and had a year to themselves as the clearly superior HD console, a year which could stretch into two if most people can't afford 720s and PS4s when they come out.
Instead, by 'cheaping out', if you will, they allow the launch and first year to be dominated by this horrible discussion of 'How the hell can it be less powerful than a 360?' no matter how erroneous that contention might be."
