This is such a strange series for me--I think it's extremely readable and engaging and yet... something is missing for me. I just can't seem to get emotionally invested in the the characters and their struggles. I also just find the whole premise kind of absurd (though there are hints that it will all be explained in the next book). I have issues with Tris, the narrator, since she reads as rather emotionally stunted (which actually makes sense in the context of the story, but it's still troublesome for me) but is a pretty ruthless/brutal fighter. And I find it frustrating that she keeps running off on her own, when it's obvious as hell that she and Tobias make a great team, with complementary skills. I know this serves to create conflict, but it's conflict that isn't necessary to me. Ultimately, I find myself caring much more about Four/Tobias, because his story is more mysterious and interesting with all it's family complexities. I wish this book has been more like 350-400 pages long and there'd been fewer battles. I sort of feel like all of Insurgent was like reading the last half of Mockingjay, with all the fighting. 
 And, honestly, the worldbuilding is a hot mess. I just can't with all that... 
 FWIW, I didn't mind at all that there wasn't any recapping from Divergent. Once I realized that Insurgent picked up right where Divergent left off, I just read the Wiki for the first book to refresh my memory.