This will be interesting, my feeling is that PS4 will win september (due to the hype around destiny and all those bundles) not as comfortable as one would expect. Mainly due to X1 launching on China which could be big or just a small boost, time will tell
October is a hard one, I think SO is releasing with the bundle but that is late in the month? I think ps4 easily. November i expect that the x1 will win, due to MCC and i am sure deals, maybe price cut etc and also December