I don't consider myself a Nintendo die-hard, more like a PC die-hard. And that means, that for me, about 99% of the content on Playstation and Xbox are already available on my PC, and in pretty to boot.
So it all comes down to the exclusives for me. And while the exclusives of Sony ain't bad by a longshot, it's just that these games are not in the kind of genres that I like. And Microsoft had nothing at all that was in the least appealing to me - plus there was the chance that those games would come to PC anyway later on. Sony additionally has the problem for me that I never can remember where those damned buttons are - QTEs are the death of me, always.
This left me with Nintendo.. I buy a console for gameplay, not graphics (again, I got my PC for that). And while the Wii U had less games, it had more variation in it's games.
It's also telling that my 3 first Wii U titles (maybe more, not sure anymore when I bought my indies) were third person titles, not Nintendo games: Tekken Tag Team Tournament Two, Injustice: Gods Among US and Sonic and Sega Allstars Racing Transformed, the latter I bought with the console.
Sure, I could have bought those games on the other consoles, too. Or on PC, for that matter. But I don't use a controller on my PC (disqualifying beat'em ups on it) and I explained about my problems with the Sony controller (crucial in those games) and Xbox as a whole before. So, Wii U by default.
Btw, the reason why I went with a Wii over PS360 is pretty similar, too. Before the PS360, console games were more different to PC games, and as a result I had both a Gamecube and a PS2. And both N64 and PSOne, both SNES and Megadrive, both NES and Master System.