Now, don't get me wrong here, I did like this book. A lot, actually. And, in fact, it was probably a 4-star book in my head until I got to the last third or so. 
 ... I just felt like this book suffered from the same problem as Aftertime. In that, as the end of the book approached, suddenly there was the climax, a brief resolution and then BAM it was over. It just didn't sit well with me, after we'd spent 400 pages worldbuilding and everything. I remember thinking around page 340 or so that the book was like 65% over and I knew there was this big conspiracy or plot or something diabolical happening in the background but I had no idea what was going on. And as a result, when all the proverbial shit did hit the fan, it felt like there wasn't enough book left to tie up all the plotlines. 
 (view spoiler)[That, and I didn't feel there was nearly enough attention devoted to all the deaths. Especially Will's. That was just unnecessary and pointless. Oh, and Four's big 'identity reveal' was obvious from about a hundred pages away. But now I'm just griping. (hide spoiler)] 
 That said. It was still good. Not mind-blowingly so. But good nonetheless. Tris annoyed me in places, but never to the extent that I felt the need to chuck the book across the room (as has been the case in some books I've read). But like I read in another review... the elements were all there, but they never quite gripped me the way a better book would have.