Splatoon - H A P P E N I N G B O Y S

I gotta go out and buy a Wii U…

…no, seriously. I'm willing to cave and buy a Wii U + Splatoon (also Sm4sh) for this.
How do I obtain it if I go for it, anyway? Is it a limited time thing or could I get it whenever?
Also, is it worth it? I mean, I still have countless major games I haven't played yet already, but that's standard procedure for an avid Steam user…