Chris Carter reviews Tekken Tag Tournament 2 for the Wii U, and crowns it the champion:
As long as you're prepared to deal with the decidedly smaller community, the Wii U Edition of Tekken Tag Tournament 2 is the best version of the game.
Makes me want to get it! Such a big download, though... :)
My biggest question that I haven't been able to find out yet, is whether there are any fight sticks coming out for the Wii U, and whether my old Tatsunoko vs. Capcom fightstick will work or not.