I was impressed. I think this is one great example of a Young Adult novel that also crosses into the literary fiction genre. That doesn't mean that the book is difficult to read or suffers from lack of plot, though. It mainly, for me, means that the depth in terms of characterization is incredible. Leonard is such a deep and complex character - he totally made the book for me. I loved that he really felt like that weird outcast kid, and not always in a lovable, quirky-cute way. He can be obnoxious. Quick also does a superb job of crafting a believable high school setting.
I read this in two sittings, and not just because I waited until the last minute before our book club meeting. Despite being complex and richly characterized, it's an easy and fairly quick read. I'd recommend having some tissues on hand, because it can be heart-wrenching. It's ultimately a beautiful story about finding family and connecting and figuring out how to deal with the hand we are dealt.
I highly recommend giving it a try. It was an across the board hit with my book club and inspired an epic meeting that lasted through several hours and a change of venue, as Panera closed before we could finish discussing.