The psvita has been on the market about 10 months longer than the wiiU, and has sold 800k more units as of march 28th according to vgc numbers. That's just over 37 months on the market, and the wiiU has had 28 months on the market. The ps vita has averaged 280K, and the wiiU has averaged 340k a month. Assuming this exact rate, the wiiU would outsell the vita in a little over a year. Current trends over the past couple months show the vita selling slightly better, but if you look at trends, this would be the third time the psvita outsells at around this time, and then the wiiU makes up the slack at the end of the year. The wiiU is going to lose support in a year and a half I predict, and the vita will probably be around for a while because of the fact that it's likely Sony's last handheld. Given all of this information, it's honestly a complete toss up, and I can't really say which one I think will pull out ahead.