This book reminded me a little of "The Body" (Stand by Me) by King. It wasn't the story itself that was similar, but rather it was the way that the author so effectively conveyed what it's like to be a kid. I felt like I really got to know the young characters in the story.
The plot was solid and kept me engaged, although I will say that it was not primarily a "scary" story. Rather, this was a coming of age, loss of innocence, kind of tale that touched me more than it frightened me. Although, once the author unleashed his "supernatural" scenes, they were really well done and had the desired effect.
The strongest part of this story, however, was the dialog. Spot on and natural.
All I know is that I had three different novels going at the same time, counting this one, and "Shada" is the story I kept coming back to until I had finished it. Kudos to the author. Looking forward to reading more from him and about these characters!