I love the concept of this book, that cities have souls, avatars that protect them, that are them. It's something I've never read before. 
I loved the avatars of New York. They were all well-written and brought their own issues and world views to the table. It was interesting to read all their different ideas and approaches to finding themselves as the chosen ones. They needed a while to figure things out and work together, but in the end they did it because New York is their home and they will fight for it. I also enjoyed the other city avatars and I'm excited to see, who else we'll get to know in the next book in this series.
The Woman in White was a great villain. The way she used the hate people already have in them and oppressing structures that are in our world, to manipulate people and get what she wants, makes her really effective and realistic. It really drove home the points of the book.