Well i think the choice is mainly yours, but let me give you some hints to help you decide. Smash bros is not an ordinary fighting game, what do i mean, I mean that smash is more like a chaos going around and fighting your way against a foe and sometimes even against the stage itself. If you own a wii u, then I would recommend you to get that one, just because you can play face to face with you friends or whoever is in your house at the time of fighting. Then, If you don't have a wii u, i think the game for the 3ds is really worth, well you can't play locally as you would do on the wii u, but the online features of the 3ds are good, I mean you can easily play along with others with not much trouble. This game also features new modes and a lot of unlockable characters and stages which is one of the coolest things of this game too. Well i hope this info helps you a little,