When it comes to NPD Amazon monthly chartz are pretty much always accurate so this information is important..
#1 - $350 AC: Unity X1 bundle
#41 - PS4
#51 - PS4 Destiny bundle
http://www.amazon.com/gp/bestsellers/2014-12/videogames/ref=zg_bs_tab_t_bsar#1
They're the only 3 console SKU's in the top 100 for December so far (as of 6th December). Looks like the X1 should have quite a significant lead over the PS4 in the US this week
I'll update this thread as the list gets updated (usually every few days)
11/12/14 update:
#1 - $350 AC: Unity X1 bundle
#40 - PS4
#53 - PS4 Destiny bundle
15/12/14 update:
#1 - $350 AC: Unity X11 bundle
#38 - PS4
#56 - PS4 Destiny bundle
19/12/14 update:
#3 - $350 AC: Unity X1 bundle
#30 - PS4
#77 - PS4 Destiny bundle
21/12/14 update:
#2 - $350 AC: Unity X1 bundle
#24 - PS4
#82 - PS4 Destiny bundle
24/12/14 update:
#1 - $350 AC: Unity X1 bundle
#19 - PS4
#88 - PS4 Destiny bundle
25/12/14 update:
#1 - $350 AC: Unity X1 bundle
#18 - PS4
#89 - PS4 Destiny bundle
31/12/14 update:
#1 - $350 AC: Unity X1 bundle
#16 - PS4
#91 - PS4 Destiny bundle
01/01/15 update:
#1 - $350 AC: Unity X1 bundle
#15 - PS4
#90 - PS4 Destiny bundle
My prediction threads:
Wii U will sell under 40m units (made on 14th September 2012)
PS Vita will sell under 20m units (made on 30th September 2012)
Wii U will sell under 7m in 2013 - I was right