I wonder how sales will be after jan 3 when it comes back to regular price. I think Microsoft will suffer more on first half of 2015 compared to PS4 sales by widening the gap because of PS4 exclusives and 3rd party games which sells better on PS4 due to superior version.
I don't really think this is a temporary price drop. I think MS have slashed the price to bring as many people's purchases forward as they can, thus winning November and December NPD, and the media presence and mind share that brings.
Sales will always be lower in January of course, but I don't think it will be very long after Jan 3rd where we see MS make the 'temporary' price cut permanent. ALthough that will obviously have very little affect after the holiday season at the same price