I might be biased from growing up on a playstation....but who cares. Playstation is forever in my heart.
I've never understood these kinds of allegiances. I was raised on Nintendo, but I sure as hell don't support their current policy of "rerelease old titles and half-ass new ones; new IPs be damned."
...and before any of you say anything, I don't care about the new Zelda or the new Pokemon.
The reason I have an allegiance to Playstation is not just because I have owned their products growing up. I have (personally) never had any major issues, and the minor issues were either so minor I didn't care or were caused by me. I have played Xbox consoles and owned Nintendo consoles dating back to the NES, and through that personal experience as a gamer I have simply come to prefer Playstation products.
Also I realize that I didn't mention anything about the subject of the thread. I think the main reason that the Wii U did so well is similar to what Blade said. Nintendo is more known for family games and parents during Christmas are (typically) looking for a console that has family type games, not FPS games like Halo, COD, etc.