So, when I finished this last night I was sure I preferred the film. Now I'm thinking they're on even footing. I'm not sure that I knew what was going on some of the time but I'm convinced I survived because I saw the film first. 
 While they have differing story lines they are very much the same principle. The book also explains Sophie's changing appearance in the film, though it's something that doesn't happen in the book. Aimed at a younger audience than the film, it's a good one to read to your children, or to give to your children to read.