This Post Contains Spoilers
(long story short-it was good)
Overall, I enjoyed the movie adaptation of "Divergent." I felt that the cast did a great job of portraying their characters and that the main ideas and themes communicated in the book were also communicated by the movie. Aesthetically, the movie was great, although I did picture the Dauntless Compound differently when I read the book. Right off the bat, the Factions are visible through the clothing that everyone is wearing, additionally the Abnegation houses were exactly what i pictured when reading the novel. I was very concerned that the zip line scene would be cut from the movie(if you have finished "Allegiant" you know why) but thankfully the zip line scene made the final cut and was everything I hoped it would be.
However, as is with most book to movie adaptations, there was a loss of detail. One of the main things missing that I picked up on immediately, was that Edward did not lose his eye. The butter knife incident did not even occur. There were also some bits of the movie that were narration explaining background and reasons for things which, as a person who read the book, these were a little annoying to sit through, but they did not ruin the movie, and I can see that they would be necessary for those who have not read the book.
There were also some plot changes. When it comes to Tris' mother saving her during the attack simulation, she saves her from being executed at gunpoint rather than breaking her out of the water-filled tank as she does in the book. Additionally the shut down of the simulation occurs in the movie as Tris and Four forcing Jeanine to turn off the simulation rather than Four having monitored and then shut down the simulation as he does in the book.
Although there were differences between the movie and the book, I do not think that these differences took away any real meaning from the movie that there was in the book. I came away from the movie impressed with how much it did manage to remain true to the book, and was entertained by the entire movie. I can't wait for the "Insurgent" and "Allegiant" movies, and will honestly most likely end up seeing "Divergent" again while it is in theaters.