If the WiiU keeps selling more, it might overtake the Via by the time Zelda U comes and then gain a million units of advantage. After that, it's just a matter of whether Sony keeps the Vita around or not. If the Vita stays a year or two after the NX release, it will come on top.

It probably will be it will take longer then you think. Wii U is overtracked on this site.

Haha, crikey. It feels like a while since we've had one of these threads. I should dig up that old prediction thread where most people thought WiiU would overtake Vita in Q1 2013 and yet here we are, heading into 2016 and it still hasn't happened.

But anyway, in answer to your question - I have no idea. I've never really seen a situation quite like Vita where the console manufacturer seems to drop all software support like 2 years ago yet the thing keep selling and getting games. So I have no idea how much longer that'll last. Maybe it'll die out next year; maybe 2017; maybe even further. I genuinely haven't got a clue.

After what?

I can't believe this is still a thing.

...Anyway, Wii U has already outsold Vita. Vita is heavy overtracked here.

Yes especially how Splatoon in Japan was able to keep the Wii U above 10k for most weeks after it released.

Wow, that's a bold claim. I'm not sure if the Wii U will pass the Vita, but if it does, it will barley pass it for a short time.

WiiU is over 11mil ssold,  where is vita at? 

Well, with the vita suspected at being massively overtracked, which I think is true, it may be very close to it already.

It will be ahead most of next year.  Wii U will probably not catch the vita until November or December 2016. If the Wii U successor releases next year the vita will win 100%. 

If it comes out in 2017 it might win. It's a great battle though.