I have owned a PS3 and a few Xbox 360's, I currently own a Wii U, 3ds XL and a Vita. I sold my old elite 360 to one of my bros. a while back (It eventually RROD'd) so I bought a 4gb slim model this last year as I fancied some online gaming, needless to say it gathered dust, especially as I realised how ripped off I felt from Microsoft over the past few years.
Firstly, controller has no rechargable battery, then I remembered paying £60 for a wireless adapter on my old Xbox 360, no HDMI cable with it, you have to pay to play online, on my 4gb i couldn't play co-op on halo without buying a HDD, I have just felt so ripped off down the years, and to be honest there isn't much variation of games on it either, at least Playstation has little big planet, these reasons made me realise the massive waste of money my 360 was, so I went and bought a Wii U (helped by trading in my xbox.)
The Wii U is everything I want in a console, all those problems I found with the 360 don't exist in the Wii U, sure it is not perfect, but it meets all my needs, and provides a great variety of games, I can play Mario and the current CoD on the same system, Nintendo have kept me satisfied since the NES, I enjoy Playstation as well, but my Xbox experience has brought me back to my gaming roots once more. Don't get me wrong, there are obviously those with the opposite opinion to mine, and that is exactly what this is, my opinion, but I am so much happier with my Wii U, especially looking forward to new Zelda and Mario games, I don't stare at it and think "why, oh why did I buy you" like I did with my 360.
These are the reasons I bought one, as I said, I know not everyone will agree. As for people moaning about the launch price, £250 is a lot better then the £425 I paid for my PS3.