I saw the "Divergent" movie and I will share my thoughts. First, I read the first book about two years ago, I have been stalled about partway through the second for a while, so while I haven't gotten to the thing that apparently makes the internet very mad, and I still intend very much to finish I have not. I did not brush up on the book before the movie which is sometimes something that lets me relax and sometimes makes me go, wait, didn't they, hmmm, is that different?
Also, if you want a review from someone who hadn't read the books, may I suggest this one.
Overall, it was enjoyable. I felt like it would be more enjoyable to fans of the book, but not incomprehensible if you hadn't read it. (You just might have more questions after.)
So, short overview - Dystopian world, in a post-World War Chicago, society divides itself into five factions so that each person can develop their personal strengths. Teens are given a test to determine their aptitude, but also have the option to make a different choice. Most choose the faction they were born into. Your choice is final. If you choose to go elsewhere, you cannot go back. Beatrice and her twin brother are about to take the test. Only Beatrice gets an odd result, she doesn't show as only one faction, she registers as divergent. Advised to keep her test results secret lest she be hunted, she has to make the choice without the guidance of the test. She chooses Dauntless, the faction in charge of security rather than the Abnegation she grew up with who handle civil service. Now the question is, can she survive the training to become Dauntless, and do so without her secret being discovered.
The movie follows Beatrice (Tris). This is just like the book, and is not a criticism, just a note, since, for example, the "Hunger Games" movie has scenes that Katniss is not present for. The closest we get here is people muttering to each other behind her back. The challenge with a book to movie conversion is that two hours is still less story than your average book, so there are things that you lose. "Divergent" employed a Tris voiceover to quickly establish the concept of factions which I thought worked until they repeated it approximately five times in a row. (Once for each faction?) Also the training fights seem reasonably, well, bad. Because most of them are bad at fighting. These looked bad both because they looked painful and they looked like they were some of them not natural fighters.
I would have to check the books, but to me the training seemed segmented. There were two phases of training in the book also, but I didn't remember Tris having all this extra time to hang out with Four at his place and just be during phase two. That could be my faulty memory too. (Also, I don't usually notice continuity stuff like hair and bruises and scabs, but I did here.)
There was more time in the book to discuss things like growing discontent among the factions, rumors being spread about Abnegation, suggestions that they had let the power of running the government go to their heads. There are mentions in the movie, but it struck me that some of these comments just seemed like inter-faction ribbing until you suddenly realize that oh wait, no - there is a giant conspiracy lurking here. This was the aspect I would expect non-book readers to be a little thrown by. There were hints, but it might seem a little, oh, yeah, so it turns out they're planning to overthrow everything, um, right now.
And well, the Four Tris relationship that was nice. I enjoyed watching it. There were some lines that seemed a bit clunky, but overall, very well done and it made me interested to see what would happen next.