Depends what games you want really. Hard to give advice other than that.
Right now the library for 3DS is stronger, so I would go with 3DS, personally.
But there is also a lot to look forward to on the Wii U front too, particularly the Wonderful 101 and Pikmin 3.
3DS has Animal Crossing, Luigi's Mansion, and Pokemon X+Y coming up, as well as a richer current library of games like Mario Kart, Super Mario 3D Land, and what have you.









