4/5 stars for me... I think. 
 I need more time to digest. But first of all, can I just say that Mal is so selfish just wanting Alina all to himself when hello, you've been best friends since they were little and you had so much time to be with her and you took her for granted. I mean, Mal is really getting on my nerves much like Adam from the Shatter Me series did. 
 (view spoiler)[ Did it really take you her actually verbalizing that she doesn't want to be with you that you pushed her that far away? And even then, my God, I loved Alina in that moment. Unlike when Tris gave herself in all those times, she really thought it through on how she would take him down and was finally willing to make those sacrifices. Alina was so boss at the end, tricking the Darkling like that. Yes, my manipulative little (now) blondie! (hide spoiler)] 
 I'll admit that it was better than its predecessor since let's be honest, I kind of enjoyed reading her struggle with power.