The movie and the book were very different but they did have a few things in common, such as the general story line and the characters were all the same. Also the Erudite gained control of the Dauntless, by means of a serum, in order to overthrow the Abnegation government.
Overall the movie had many similar things but there were a few large parts that were different. One thing that's different is Tris captures the flag instead of Christina stealing it from her. This makes a huge difference because when Christina does that it adds a level of betrayal and jealousy into the book whereas the movie doesn't have that. Also it foreshadows Will's death and so the movie doesn't have that.
Another thing that's different is that Peter is never shown to be so mean in the movie. In the book he's like this evil guy who almost everyone hates whereas in the movie he just seems a little rough around the edges. This is a big difference because it takes away the whole rivalry thing that goes on in the book. Also it just takes away from the overall character development that happens in the book.
In conclusion I thought that the book and movie were alike but some key parts were changed a little to much. I liked the book way better but the movie did have some things that I liked better than the book. This was a great story! What did you think?