Can't actually remember why I picked up a copy of this, but very glad I did so.
Structurally it's a detective story a who-and-why-dunnit, thematically it's low-fantasy bordering on the noir - trust nobody, admire nothing. Everybody is plotting; everybody has an agenda.
But what it is above all is *new*, this is not a world quite like any I've read before. The rules of the world are all shown and experienced, there's very little tell. This has costs and benefits - on the plus side you are never, ever bored; on the downside, there's never quite enough information about the world to know whether a trick is legit or not. But I'm quibbling a little here.
If there is a criticism, it's that the protagonists do remain a little vague. I know I've been implying that this is very much a plot driven, not a character driven book, so complaining that there is a lack of characterisation may be a little harsh. Still, there's a final (inconsequential for the plot) decision Tara makes at the end of the book and although she justifies it, it could have been the exact opposite; there wasn't enough of a feel for her character to constrain her decision either way.
Bottom line, it was a really entertaining read and I'll be buying his next book for sure.