I'm surprised at how much of the pithy, funny dialogue came straight from the novel. I'm also surprised at the potentially bleak ending the book had. I think all the changes they made for the movie were excellent choices. All in all, it's a very good book.
One of the best Lovecraft anthologies I've read in ages. Although, unlike the editor, I mostly hated those that actually incorporated/turned HP himself into a character in the story. The majority of the other tales were excellent.