I finished reading Perdido Street Station today. Finally. It's been months. It's a fantastic book, and I'd recommend it to anyone. ...Well, okay, not everyone. It's a difficult book, and I know some people who might not be able to wade through it. But if you're in the mood for some very literary SF/F/Horror writing, Perdido Street Station should be near the top of your list.
And now: Spoilers.
In the book, Miéville runs circles around genre conventions, seemingly doing everything wrong. It's a very black-and-gray morality work, where it's made clear it would be impossible to do anything right in this setting without doing some things horribly, horribly wrong.
One of the most extraordinary things about Miéville's writing is his use of deus ex machina -- the plot of Perdido Street Station is riddled with much more powerful entities than any of the major characters -- the Weaver, the Council, Jack Half-A-Prayer, who show up out of nowhere to save the day at every seemingly insoluble plot point. But their inscrutability and complex motives are consistently explored, and their strange behaviors are consistently justified -- and they have consequences reaching past the moment of their intervention.
Altogether I was thoroughly impressed with this book, and recommend it highly.