The story itself was exciting and each chapter ended with a cliff hanger. I kept turning those pages but there were a couple of things that, as a reader, made me impatient to move on. For example, Jonah's thoughts seemed to go off on tangents or repeat when I wanted to get back to the story. The other thing was discussions about paradoxes, time travel, ripple effects, etc. I think young readers will just skip over those parts to get to the action.
On the other hand, being a "grown-up", my POV in those two areas may be way off base.
As a writer, I learned some things about technique, characterization, and what keeps a reader glued to the page.
I recommend FOUND and enjoyed it so much that I'm settling back today to read the sequel, SENT, published in 2009.