My note on this is that it was recommended to me via Bookaneer's Review. So that only took me two years to get around to reading it, and I'm kicking myself. Hard.
I'd review it, but seriously, just go read what she said. My review would just be superfluous over hers anyway :)
Suffice to say, I just went and grabbed another Daryl Gregory book (Pandemonium) immediately after finishing this novella, and I wouldn't be surprised if I end up with a couple or three more over the next few days.