As a big fan of The Polar Express, I REALLY wanted to like A Christmas Carol, since the same animation studio did both. However for me, A Christmas Carol with Jim Carrey just didn't quite hit the mark. I didn't like that the movie strayed so far from the book with the ridiculous chase sequence when Scrooge shrinks down to the size of a mouse. Plus, I thought the character model of Bob Cratchit just looked weird! I think they were trying to make it look a bit like Gary Oldman, who voiced the character, but to me he ended up looking more like Alfred E. Newman from Mad Magazine.
For A Christmas Carol, there are two that I watch every year. The first one, and I think it's the best one of them all, is the one with George C. Scott. The other is the old black and white 1938 version starring Reginald Owen and Gene Lockhart.
As far as animated Christmas Carols, I'd rather watch Mickey's Christmas Carol or Mr. Magoo's Christmas Carol.