I haven't read the book, so I can't comment on whether the adaption was good or bad. The Dive from Clausen's Pier was in my opinion a good movie on the whole. It's not normally my kind of movie, I watched it mostly because of Michelle Trachtenberg. The story is about how an accident changes the lives of a group of people, and especially Mike Mayor (Will Estes) and his girlfriend Carrie Beal (Michelle Trachtenberg). It was in my opinion a bit too short, and I wish some characters could have been explored and developed more. Other than that, it was good.
I was pleased to see Trachtenberg in this movie, and from all her film and TV works, I consider this to be one of her best performances, possibly to share the first spot with Mysterious Skin. She's not just a beautiful face, she's a talented actress and I believe that with time she will grow and develop even more.