What I have learned from certain fans is that when ps4 was $100 cheaper price wasn't the reason it sold better. On the other hand XB1 managed to get its price lower than ps4 and it is the only reason it outsold ps4.
On topic I think XB1 will win December easily. In November ps4 had a bundle with the best selling game ever, GTAV, and was still outsold by 400k. This month XB1 still has deals and ps4 just has the destiny bundle. I say another 250k will be cut in that ps4 lead.







