Walton's books remain really interesting works of...inquiry, I suppose. She's very good at taking a premise (what if we actually established Plato's Republic, e.g.) and building it into a story. And I enjoy figuring out where she goes with it and how it becomes an actual story, with plot and everything.
The good is very good. Her biggest shortcoming, and it is a problem I seem to have with most of her books, is how difficult I find it to get emotionally invested in the characters. This book, perhaps because of the sheer number of viewpoints, was worse than usual. I felt like the individual characters lacked defining voices and, while I was curious about the fate of the city and the people in it, I found it hard to be invested in them as individuals.
Still, the premise and story make up for a lot and I'm looking forward to the sequel.