Maybe but we can easily claim that PS4 will dominate X1, that's for sure, obvious, mass lead in europe +Japan, even if in the best scenario for Microsoft X1 beat PS4 in US.
I'll wait for Mario Kart to judge about X1vs Wii U, since Wii U has Japan
Predictions for end of 2014 HW sales:
PS4: 17m XB1: 10m WiiU: 10m Vita: 10m