I did not enjoy this movie at all. I am a huge fan of the book and at first was excited that Disney decided to make a movie from it. I was shocked that the movie was not like the book AT ALL. I really did not like the actors and actresses chosen to depict the characters. Mischa Barton does in fact have a similar appearance to the Vicky in the book, but is not a very good actress and her performance was unenjoyable. I expected Zachary Gray to be more "dark" and "pale" as he is described in the book and I was disappointed that Jared Padalecki was chosen for this part. There were a lot of characters either added or taken out of the story. Whatever happened to Leo and Jacky Rodney, Mrs. Rodney, and the death of Commander Rodney? Or what about Binnie at the hospital? Or even Mr. and Mrs. Austin, who only appear in the movie at the very end. Scarlett Pomers was also not a good choice to play Suzy. She appears as red-headed, frizzy-haired and four-eyed instead of the petite, dark-haired, purple-eyed tween genius she was described as in the book. There were also a lot of different things added to the movie, such as the whole story about the drift nets which did not appear in the book at all. I think Disney captured this whole idea about changing the movie from the story of a teenage girl coping with her grandfather's leukemia into the story of a girl choosing between two boys and having to deal with the captain of some ship leaving drift nets in the water and potentially capturing the dolphins.
To conclude, I was extremely disappointed with this movie. In my opinion, read the book. It's one of the best pieces of written fiction I've read, and is much more satisfying as a story than the movie ever will be.