My opinion, would be the PS4. I think it will pass 100 million. The market for PS4+xb1 seams to be about 150-170 million. If Xbox manages to get to 50 then PS4 should get to 100, maybe 110. I think what happened to the wii will happen to the switch. It will sell great right up until it falls off the cliff. I think 80 million for switch. But I'm of the opinion that it's a gimmick. So what do I know.
Halo MCC will sell 5+ million copies(including digital)
halo 5 will sell 10 million copies(including digital)
x1 will pass ps4 in USA, and UK.