RIGHT NOW according to Vgchartz:
Wii U: 6 900 000
xb1: 5 000 000
_________________
diff: 1 900 000
Now, assuming the xb1 sold 150 000 units on average from now until December 31st (I think this is giving it too much credit) it would sell 3 225 000 units.
If the Wii U had no holiday boost and kept selling 61 000 it would sell 1 311 500
Total on Dec 31st:
Wii U: 8 211 500
xb1: 8 225 000
That unlikely scenario would give a very slight edge to the xb1, but I expect the Wii U to do better than this and I would be surprised if the xb1 did as well as I predicted. It's even possible for the Wii U to keep selling more than the xb1 on a weekly basis, not that I care much, if these were the only two consoles on the marked right now I would probably just be playing on PC.
