John Swansburg thinks the 1966 animated version of The Grinch Who Stole Christmas was superior to the book on which it was based. I like the special a lot and I think that if you had to turn the book into a cartoon of that length, you couldn't have done a better job of it…but better than the book? I don't think so.
Reportedly, Ted "Dr. Seuss" Geisel wasn't happy with the finished product, even though he participated in the adaptation by writing song lyrics. He was also listed as producer along with director Chuck Jones though that credit could have meant almost any level of involvement. I never met the Good Doctor but folks who did have told of him complaining about all the stuff that was added and how his designs morphed somewhat into Chuck Jones designs.
I think both those things are inevitable when you commit so short a book to a half-hour timeslot and hand creative control to a director as immersed in his own style as Chuck Jones. No matter what Jones did the last few decades of his life, everyone looked a little like Wile E. Coyote.
The resultant special won great accolades and awards and demands for its rerunning every year for a long time. It probably even sold a lot more copies of the book. But better than that book? Like I said: I don't think so.