Since everyone knows the story, I’ll dispense with the usual plot and character analysis.
This book was on my to-read list for many years. I’m glad I finally read it. First, I was surprised how closely some of the movies follow the book. The only differences were some of the adventures with ghosts. For instance, the ghost of Christmas Past took Scrooge on a short trip to a ship at sea, which was never (as far as I know) portrayed in any movie. Many sections of the book take advantage of the written form to provide descriptions that couldn’t be provided in video. And a proper portrayal of the ghosts would require some interesting special effects.
I think that some of the extras provided by the films are good addition to the story. There is often an expansion of Scrooge’s relationship with Tiny TIm, who becomes more of a focal point than in the book.
Although the book is a good read, the story is well known enough that I think I would have gotten more value out of one of his others. But I’m still glad I read it.