This was an okay novel. Pacing was nice, the novel hummed along, but at the sacrifice of character development. I never cared about any of the characters.
Until the end, the book was less a coherent whole and more of a series of stand-alone scenes that followed a predictable course: The Hollower scares someone, then goes away. Rinse and repeat until the characters grow tired of the act and storm The Hollower's hideaway with no plan or clue how to kill it. If you think that sounds implausible, you are correct.
A little more background and info on the Hollower would have been nice. I'm still not sure I know what the heck it is, or why it does what it does.
Another reviewer mentioned this felt more like a Hollywood script, and that's right on. Even down to the obligatory sequel-suggesting ending.
The book was well-written and moved along nicely, but really needed some stronger characters and better plot management.