The beginning was so dull and gave me whiplash from all the POV jumps, but Mary Kubica did a great job of keeping each storyline progressing steadily so it never felt stagnant once we understood who was who.  The tension built beautifully (I literally kept gasping at one reveal in the office, alarming my coworker).  I found the ending mostly satisfying (probably one of the most satisfying endings I've read in a thriller in a while) but it still wasn't earth shattering or mind-bending.