Regardless of the debate what the general public thinks will be the more attractive console, it's pretty much a given that PS4 will outsell Xbox1 in 2013 because Xbox1 is launching in fewer places compared to PS4. Probably also in 2014, Xbox1 will still have a manufactoring shortage compared to the PS4, so the PS4 should still outsell the Xbox1.
Here in the US, it's debatable whether PS4 will outsell Xbox1 (although the presale numbers seem to suggest that PS4 will outsell Xbox1 here in the states). Outside the US, Xbox1 isn't even being sold in some countries, so PS4 should greatly outsell the Xbox1. 2 to 1? Or even 4 to 1?
By the 2nd half of 2014 and thru 2015, the supply for either systems shouldn't be an issue, so the more attractive system (whether because of exclusive games, kinect, or etc) should outsell the other. But this point the Xbox1 has some catching up to do.