I found this book mostly as engaging as the first one, but also more frustrating. Tris was harder to relate to, partly because she spends the entire book overwhelmed by grief and guilt (which is understandable, just not totally relatable for someone who isn't going through the same thing), and partly because she just won't stop lying her ass off to everyone she cares about. Her Abnegation issues in the first half of the book--where she keeps wanting to sacrifice herself for everyone and anyone else--were infuriatingly reminiscent of Stephenie Meyer. 
 But the story is still great, and though I started to figure out where it was going long before the end, there were some good surprises. I'm looking forward to the next book--which I wish I'd known wasn't coming out until October before I started reading the series, because then I would have just waited. Waiting to read the series is much less annoying than waiting for the conclusion of the series.