I absolutely loved this book, despite the slow start. I think the blurb does a bad job with this book; I expected the events described to be only the first few chapters. Instead, the blurb turned out to be a very vague summary of the whole book.
I enjoyed the writing style; it was very clean and polished while still seeming organic. The pacing, after reading the whole thing, was done well.
As for characters: though I didn't relate much to Claire, I loved her. I cared about her and I wanted to see more of her adventures. Her school friends I didn't care much for, as I've always hated girls like that. But the gang of kids Claire ends up taking care of? I loved them all, despite the fact that they are thieves (especially Willie, he's adorable). Lord James I hated; he was a jerk in my opinion, but it was done well. I liked Andrew, though!
All in all, I really enjoyed this book! Though I don't like the cover art.