Very nice of the guys to do this for their crew.
My only complaint (and it isn't really one) is that they attempt to strike a balance between whimsical stuff like Jingle Bells and bigger, more "epic" stuff like O Come All Ye Faithful. I'm not quite sure that they hit the balance, and I would have liked to see them go one way or the other. But I still like it a lot, and they get mad respect for doing it at all.
More grandiose traditional carols like O Come All Ye Faithful, Joy to the World, We Three Kings, etc already lend themselves well to DT's style (and of course, they've already done O Holy Night). I would love to see an entire Christmas album from them of those types of songs.