My verdict: Having a live actor take the part of the main character (Michael Cain), was an interesting choice for a Muppet movie. Cain makes a better mean Scrooge than reformed, but overall does a good job. I'm impressed with how many Muppet characters were created for this movie—especially considering that many of them only saw a few seconds of screen time. The two big Muppets (ghosts of Christmas present and future) just didn't work for me, and there was a bizarre instance of a lobster leaning out of a snow-laden window, but other than that I thought they did a pretty good job. They also make good use of many of the conventional Muppet characters. Gonzo and Rizzo the Rat provide some nice meta-story comedy. Turning Statler and Waldorf into two Marleys (the second is Robert Marley, i.e. Bob Marley) was kind of fun and changing Fezziwig to Fozziewig was clever. And I always like seeing Dr. Bunsen Honeydew and Beaker, the Swedish Chef, and Animal make their cameos.
 The only other version of A Christmas Carol that they own is the 1970 musical, Scrooge (read my review here).