I haven't read the book, but a friend of mine did and she said it followed the book fairly closely. I enjoyed the movie. It was funny, shocking, and a tearjerker all at once, with some wonderful actresses. Go see it!
It was funny but, as others have said, not as good as the Hangover and most of the funny parts are in the previews. Worth seeing, though. Loved the soundtrack.
I really enjoyed this movie. My husband said he thought it was too complicated, and I read other reviews that said it was hard to follow, but I totally disagree. I found it intriguing and thought provoking. It wasn't overly complex since everything meant something and was important, even if you didn't realize it till later. Although I did anticipate one of the twists at the end, I did not anticipate the final twist, which was one of those "ohhhhhhh" moments. There are very few movies anymore which I really enjoy, but I definitely recommend this one.