Yes, the book was amazing. I've recommended the book to anyone who enjoyed the movie, and to quite a few who've never seen the movie. Davidge has a very distinctive, grumpy voice that I don't think comes across in the movie, simply because, to really get it, there would have to be constant, rather than intermittent, narration.
I don't blame the filmmakers for the changes they made simply because I think the novel's version would have dragged down the preceding action/adventure style of the film. I do wish, though, that they'd retained the Mickey Mouse scene as it was originally written.