I had my Wii U since last year.
I'm interested in the other two... But no way I'm dropping $550/$600 for either.
I'm just starting to get tired of having to constantly update my stuff on consoles. I miss the days when I could just pop a cart in my GBA and have it flip past the logo and boot up the game. Now you need to go through menus just to have your game start loading. I know the old consoles had issues and aren't nearly as powerful as new ones, but the current gen ones just feel too much like multimedia devices, which PCs are
always going to be better at. Also, new consoles have some fatal issues- the old ones did too, but on new ones, you have much more to potentially lose- like your digital downloads, and internally-saved game data.
I'm also really tired of games trying to be movies, if you know what I mean. Having stories that are good stories but don't really impact the gameplay, and would be better as movies. The Last of Us is a great example of this(I haven't actually played it, so forgive me for using this example, though it just looks like it would be better as a movie): a good story, but why not in a movie? It doesn't make the player a part of it, like, for instance, Skylanders: Spyro's Adventure did(YOU were a Portal Master, YOU were directly referenced in the story). They've been especially prominent for the last few years outside of a select few areas, which is why I stick to Ninty consoles. They're good at being able to a) make stories add to the experience when they are there (i.e. the stories in Zelda make it feel more like an ADVENTURE and give it cool lore) and b) not making the story a big deal when it really isn't nessicary/would be obtrusive and annoying(Super Mario). Indie games are also particularly good at avoiding this trap, and they're very common on PC with Steam and Kickstarter and whatnot. I don't mind a prominent story too much if it adds to the experience of the game or the game is awesome on its own, but there are many I would rather see become movies in games lately, and just stay out of my games where I want gameplay. At least give us an option to "turn off" (not skip) cutscenes, if your game is actually a good game and not a movie-in-denial.
I also don't have a big reason to upgrade either my PS3 or 360. While I would like to have the newer tech and newer games, I've barely scratched the surface of the old systems' libraries. I still need to play games like LittleBigPlanet which I know will be huge timesinks on their own. It's hard keeping up with every game I'd like to try as it is. I would be more willing to upgrade next year or something if PS4/XBone had backwards compatability with my physical disc collection, but they don't. >.>
I'm not saying Nintendo are a patron saint immune from these issues- because
they're not- but I can only accept these problems so many times at once before it's too much to just enjoy my consoles. So I stick with the Big N, because they have consistent quality for the most part, and I like their games the best.
If it counts, though- I am going to upgrade to a Vita either for Christmas or my next birthday because I hate the thumb stick of the original PSP that I've been stuck with.