Last year was pretty much the same as most of Europe i.e. almost non-existent until much later in the season. However, there has been very good snow in all Bulgarian resorts in previous years around that time. As i'm sure you will appreciate the weather, and snow cover, changes year on year.
If you can only go over New Year then my advice would be to try either Bansko or Borovets as they are both at a much higher altitude than Pamporovo and the higher the resort the better your chances ...
Last year was pretty much the same as most of Europe i.e. almost non-existent until much later in the season. However, there has been very good snow in all Bulgarian resorts in previous years around that time. As i'm sure you will appreciate the weather, and snow cover, changes year on year.
If you can only go over New Year then my advice would be to try either Bansko or Borovets as they are both at a much higher altitude than Pamporovo and the higher the resort the better your chances of getting snow.
The snow in Borovets was pretty good last New Year. Check out the webcam archive here http://www.bulgariaski.com/webcam.php?lang=en&resort=Borovets&img=1167818466