I'm not particularily interested in those when it comes to Suggestion Threads, Guildy-Locks.Anyway I'm expecting some soulx/Foxi4 beef off between the 3DS + Wii U vs. Vita which resolves in a typical pretentious ego-off while I go to another thread because I don't actually do shit in these threads.
Oh and Valwin will pepper in some troll lingo here and there.
In any case, invest money in the console that has games you're interested in, really. Nintendo consoles mean Nintendo games - if you're strongly attached to those, go for a Nintendo console.
Out of the three, I'd get a 3DS and a PSVita, mainly because I rarely find the time to do some serious gaming in front of a monitor or a TV - I prefere handhelds.