I haven't read many books set in NYC, 1845. Loved the lyrical descriptions of the city. Was captivated by the multi-faceted characters. Impressed with the pace of the book, had the perfect amount of action interspersed with the visual. I could see this being made into a movie, but then it would lose what I loved most about it: the prose.
And I'm not even done.
Update: Really liked it!