I think it was good episode and great way to bring back the Daleks into the show. We last saw 12 conversing with Rusty and earlier with Davros.
The New Year mentions were light with the firework display and just plain mention of New Years.
The attempt to bring in UNIT was a bit funny.
But the additional class of a Recon DALEK was interesting. This Dalek was a bit more frightening than previous seen DALEKs. Bigger squidy thing and cling onto and control people.
It was a good episode. A bit plain for a Special IMO. I was hoping for an ARC reveal.
I rather enjoy the previous Christmas Specials for their comedy or ARC reveals/conclusions.