Good book, although I preferred his Neverwhere to American Gods. It is an interesting scenario—kind of Harry Potter-ish in that all this occurs in plain view of the rest of the world without the rest of the world catching on. Good social commentary through the “New Gods.” Good story. Compelling and oddly sympathetic characters. A bit gothic in feel.
But I agree with MadCarlotta that it is very transparent and visual—it reads like it could easily be taken to the silver screen or another graphic format. Neverwhere reads the same way and is a BBC series (not sure which is the chicken and which is the egg for that book/TV tie-in).
As with most fantasy/scifi/horror, I thought the ending was a little weak—better than Crighton and King, two other visual authors, but not as strong as one could hope.