I'm going to get a Wii U, but nothing else.
It's mostly a matter of "How do I feel about what the three companies did during the last generation, and what their console brought me?" I saw Microsoft charging for online and inserting ads onto the dashboard, Sony pushing console prices over twice what they were during the last generation and struggling with basic online securtiy, and both companies having rather horrid failure rates. All the while, 3rd parties were putting ads in their games, day-1 DLC, on-disc DLC, DLC required to complete main story modes, overpriced DLC, and releasing glitch-filled messes with the promise that, 'We'll patch it in...a few months...".
At the same time, the fanbases of these consoles grew to annoy me. No, not the typical fans, but the horrid fanboys that patrol the message boards of the internet. The sort of people who make it their job to insult the other companies' products (for example, calling the Wii U childish, claiming not a single decent game existed on the Wii, mocking Sony's E3 2012 presentation just because of Wonderbook, mocking Microsoft's E3 2012 presentation just because of Usher), bicker over profit margins, create conspiracy theories as to why their game only got a 9.7 instead of the 10 it deserves, and argue about what counts as 'winning' a generation. At the same time, the emphasis on graphics that existed during previous generations seemed to grow into an obsession (no doubt fuelled by the Wii's less-than-stellar graphical capabilities), with a game's quality often being decided upon graphics alone. This doesn't even get into the 'hardcore' and 'casual' argument, having to deal with sexist, xenophobic, homophobic 12-year-olds online, etc.
Now, that's not to say nothing good came of the PS3 and 360. They had some very nice RPGs. Glitches aside, the Elder Scrolls is one of my all-time favorite series. Valve kept on making fantastic games (but never, never more than twice). Halo was pretty good (at least, for a while). Indie games thrived on these platforms more than ever before. Likewise, I'm not saying that Nintendo fanboys don't do any of the things I listed above. One look at the GameFAQs Vita board (*shudder*) would tell you otherwise. But it appears, to me at least, that the bad outweighs the good, and the Nintendo fanbase is, if not less vile than the Sony or Microsoft fanbase, at least more tolerable.
Will I someday buy a PS4 / XBox 720 (or whatever they decide to call them)? Probably. But I doubt it'll be before this new generation ends.