Having only recently read the novel a few months ago, perhaps I should have waited to see the movie because the plot and the characters were so fresh in my mind. Since the screenplay truthfully followed the book, no surprises were in store for me. I agree that Ang Lee did a great job in telling this story on screen. I, for the most part, was not able to tell what was real and what was movie magic. Visually, it is a stunning film. The young man who played Pi had no acting experience, but he was up to the task. This is a role that demands much of an actor because basically it is just Pi and the tiger for most of the film. Couple this also with the physical demands of the role. Suraj Sharma did a wonderful job in his portrayal.
I am glad that the end of the story was not changed. It, I believe, is important for the reader/viewer to decide which version of this tale is real. My only reservation was that some parts of the film moved too slowly. Otherwise, I think most viewers will like this movie, whether you have read the book or not.