For the record: the book was better than the movie, I thought.
They took lots of liberties in making the movie; they even went so far as to change the entire ending. In retrospect, while there were some very funny parts to the book, it's not a funny story, overall. It's actually a very sad story, mostly because it's true.
The movie was fine, but the book was much better.
If you're trying to decide which one to dive into, I vote for the book. Hands down.