But see that's just it. It realistically doesn't run "better" on any console. They are all about the same to anyone actually playing the games. They're identical.
Except... on WiiU you can play on gamepad only (easily most comfortable way to play), with "standard" controller, or with wiimote/nunchuk.
On WiiU you can play local multiplayer without splitscreen.
Sorry, but WiiU is the superior choice overall.
The only thing any gamer would notice is the average lower player count for multiplayer. But that doesn't mean there are no great online matchs to play. Just not as many at 3 in morning.