Book-to-Movie Law states that once you have read the book, you are bound by the media to go see the movie based on said book, and therefor compare to two.
I will admit it now- I had very low expectations for this movie, which can be blamed on one thing: casting. From the very first trailer, I thought the characters cast were WAY to old for high schoolers. That's a quick way to take me out of the movie. Granted, Paul Rust was only born in 1981 (not THAT old), but they seriously could have chosen someone more suited to the high school-looking atmosphere. that having been said, it was a fairly close adaptation to the book. It has been a few years since I've read the book, but all of the important moments were there. I adored Hayden Panettiere in her role as Beth. In the book, I thought the Evan Dorkin drawings were way more graphic than what Denis actually went through in the movie, but I was okay with less gore. The scenes that made me laugh out loud were worth sitting through the slower, more awkward moments.
Bottom line? The book is still better.