I definitely missed the boat somehow on this book. Rather than feeling smarter than all my friends who rated this four or five stars (they all did)--which is what bad or mediocre reviews of well-loved books sometimes sound like--I feel dumber, because I sense that there must be something I'm missing.
I read the first third of the book in one gulp and remember being fascinated. Several weeks went by before I was able to get back to it. That might have had something to do with it, or maybe I was just in the right mood to read it originally, and the wrong mood later. I did go back and after finishing and read the first third again, to recapture my enjoyment of it--maybe the first third was that much better?--but wasn't taken with anything.
The art, while excellently done, is not in a style that I find particularly engaging, and I thought having them go all the way across two pages made them difficult to look at--I couldn't see the gutters well. (I hope these books are well-bound or they're going to be destroyed in a few years from having the spine strained to show the pictures.)
The writing... I honestly didn't think it was anything to get excited about. It isn't really bad, but I didn't have much sense of the story moving forward, and with the exception of Ben, the characters didn't feel well-fleshed-out or natural to me, especially Ben's friend Jamie.
[SPOILER ALERT] On a personal-squick level, it bothered me that Ben's mom, who is supposed to be so wonderful, didn't (the book implies) tell Ben's dad about him--and then she even met his parents, who'd just lost their only son, and didn't tell them "this little boy right here, this is your grandson"? It isn't remotely suggested that anyone would have tried to take him away from his mother or anything; how could she be so selfish? It didn't jibe for me with the way her character is described. And, it occurs to me: if she HAD told them (as I felt her character-as-described would have), the essential drama of the book would be totally gone, since Ben's grandparents would have found a way to be in his life and he never would have had to go looking for anyone. So this feels like one of the things I dislike most in books: manufactured drama. I guess it isn't just a personal squick thing.
It's an enjoyable book, and certain kids (many kids) will love poring over the illustrations for the little hidden details and clues. I might have myself, as a child. But I don't think the text belongs on the Newbery table.