Intrinsic on 31 October 2014
Of course its going to be the Wii. Just no way the PS hts 50M in the next 17/18 months. I expect it to cross 50M in 2016 though, just not by march.
For what its worth I also expect it to sell more than the wii in its lifetime. I have it pegged at 125M lifetime for the PS4.