It is clear these books were rushed out as a copy cat hoping to capitalize on the wildly successful Hunger Games series. The formula was the same. A dystopian future society where people have been arbitrarily divided and oppressed and a young girl who is ready to challenge the whole thing.
Hunger Games was much more thoughtful and layered, however. At its core it was a story about totalitarian regimes based on Susan Collins very real experience of living in a communist country as a military brat growing up.
Divergent lacked any such layers or depth, but did in some ways make for a more entertaining movie. But at its core it was essentially just a high school coming of age story masquerading as Sci-Fi. You had the high school cliques - the jocks, the nerds, the hippies, the do-gooders and you have Tris Prior who doesn't seem to belong to any one group and is "factionless" (which in dystopian future Chicago seems to be the equivalent of having to sit alone at lunch).
Divergent also gets points for all of the guys around our female heroine not being totally worthless, Four is quite capable and Peter proves himself to be of some use in Insurgent.
But Tris is not going to be content to shoot a bow & arrow from a distance. That more believable combat is traded for Tris routinely beating up men with ease, which always strains credibility.
The love story is better in Divergent, as at least our young heroine doesn't fall for a completely useful wet noodle of a guy.
My praise ends there, however, as the story at its core makes zero sense. Essentially 200 years ago, founders created an "experiment" that they would not live to see the outcome of and apparently expected to fail.
That experiment is in full on failure as "Jeanine" (has there been a worse name for a villain in movie history?) is seeking to crack down on the Divergents and maintain power over the 3 remaining factions (we did away with 2 in the first movie and yet nobody in the remaining 3 factions seems to think that anything is amiss).
But Jeanine is going be challenged by a teenage girl who in true Joan of Arc style (the original Katniss Everdeen) is set to rally an army with her boyfriend Four and the help of his mother, played by Naomi Watts, exactly 16 years older than Theo James. Seems plausible, but not if you age like a Hollywood actress, she looks like his big sister.
The movie spends the last half ripping off The Matrix, including the scene where Neo dies, in order for Katniss, er Tris to fulfill her destiny of decoding the founders message. We imprison Jeanine at the end, thus we are 2 movies ahead of the Hunger Games which might explain why there is no box office rationale for the 4th film which would complete the series.
Although of course, we can't just imprison Jeanine, because presumably Four's mom now wants to take up the Juliane Moore role of dictatorette.
Divergent had enough action and pace to warrant cinematic consideration, but the weak foundation of the series cannot support two stories. Other than getting to live in dystopian Chicago, it is unclear what benefit Jeanine actually receives by oppressing 5 factions of people.
As others have noted, the zombie train system makes no sense and for being a totalitarian state, the government in Insurgent is decidedly void of surveillance technology.
If you liked Divergent, stop there, leave it at that, and take the wins when you can get them.