I think this is my favorite in the series. Since it is a sequel I can't really say anything else but I just extremely enjoyed this one. 
 (view spoiler)[ There's a lot more rebel attacks in this one. We learn about Gregory Illea. America slaps Celeste which I just loved. And America decides what she can't stand about still being in a competition where Celeste is still in the running. Shit goes down with Marlee and the secret she's hiding. Then America decides to start hanging out with Aspen because she's mad at Maxon for not stepping in with Marlee and you are just like really, really America you don't think that you won't get caught. Someone just got caught and you saw what they did to her and Carson. And then the fucking Maxon Aspen love triangle just so over it. I've never like Aspen sure he was her first love but I'm just like that's cuz someone similar to Maxon was not in the picture. I also got really sick of Maxon saying he doesn't want to be bullied, dude just listen to her side or whoever's side, doesn't mean you in anyway need to follow through on that just listen to their side. It just shows his immaturity. Just really great sequel I think it's better than the first book. (hide spoiler)] 
 I think Kiera Cass' writing really improved during this section of the story. And already moved on to the final book in America's journey. One thing that I would have changed would be that I think there should have been more than just America's point of view showcased. I know there are two novellas but I think it definitely would have added to the trilogy so far if we had seen Maxon or Aspen's side of the story. But I really friggin' hate Aspen his scenes with America are the ones I'm like 'really really' you can't just be killed off now.