Character Development: spotty. We don't always know a character's backstory or motivations, and there's not enough there to make up our own minds. Some of the secondary characters deserved (or needed) greater prominence.
Pacing: this book crawled through 75% of the story, then suddenly sprinted toward the finish. It was short, but I can't tell whether it was too short or not short enough. There were some strange twists that made no sense whatsoever to me.
it was good, but not good enough for me. Of course, this book fell outside my usual genre, so that may colour my perspective.
It's one of those books you can read on a long subway commute.
The overwhelming fear was the best part of the whole book - i understood why Ree was afraid and could relate to her distress (though not always to her choices).
Will I continue with the series? Yes, but not for a while. Too many other books calling my name!