I just bought a copy of this on DVD from eBay (Thank God for eBay!) and this is wonderful. I am a fan of Kristy McNichol and it is delightful to see her and her brother on this show. This is just great. The Carpenters have their moments too and so does Gene Kelly, but its Kristy who really brings this to life.
One of the things I enjoyed most about this was the singing. The clothes are really 70s. There is no other word for what Jimmy McNichol is wearing. Not good or bad, just so 70s. One of the best parts of the show is a number called "The Angel in the Christmas Play" performed by Karen Carpenter, Kristy McNichol and Georgia Engel. It is really wonderful. I reminds me of vaudeville. Very lighthearted and fun. And the "Big Brothers/Kid Sisters" number between Kristy & Jimmy and Karen and Richard is fun as well.