I would have loved this book as a child, and I still love it as a grownup (Gaiman tends to write like that). It is paced well, written wonderfully and rings true (in a very similar way American Gods does, but a bit toned-down to the way children see the world). Technically it is a coming-of-age story. I spent a long afternoon reading it and feel a lot better for the time spent.
For younger kids, Coraline has a similar vibe.