Eh, technically both.
I actually own a 3DS so I'll be getting that version for sure. But technically the little brother owns the WiiU and he and the folks moved halfway across town last week. So I'm thinking, "let the mother buy the WiiU version since sadly I'll hardly get to play it." Though since it might come out in November and not near the Holiday season, I'll probably buy it anyway since the mother is probably more concerned about furnishing her house than buying a game.
Either way, I'm still going to steal the WiiU version's Nintendo Club code for the Smash Bros. OST.