Interesting, captivating read. Overall it's nothing special (and I found several inconsistencies noted below), but interesting idea and compellingly written.
After the first few Miles chapters I realized that George Orson was Hayden; I did not figure out that Jay was also Hayden until quite near the end..kudos for the surprise. The layers of the story were neat and what appears to be three parallel storylines come together nicely as the same story just out of sequence. Chaon clues the reader into the fact that he may go out of sequence with the Ryan storyline immediately as we start with the severed hand and then back track.
Some inconsistencies (certainly if an editor had caught these it would have made the story more air tight and overall better):
1. Lucy's foray into the study when George leaves it unlocked is not consistent with her earlier entry into the study when he is out in the garage. Chaon describes the locked study as a point of contention between them, but it was not locked earlier.
2. Miles, at first, remembers Hayden's adolescent as surprisingly calm. He says that Hayden was uncharacteristically accepting of their mother's attic restraints. Yet, later he remembers it "as if Hayden had never lain ranting in an attic room, his hands cuffed..." Clearly these are two very different descriptions.
3. When Miles wakes up with Lydia in the hotel room he first "watched as she made an attempt to unobtrusively tuck the weapon into her attache" and then about six paragraphs later "Lydia laid the gun on the bed and held up her hands." She should no longer be holding the gun.
Not an intellectual book, although it tries to say something about both happiness and identity I think it falls way short of more literary attempts at either of these topics. BUT, two interesting quotes: "you wake up and feel fairly happy--happy in that bland, daily way that doesn't even recognize itself as happiness."..."happy is a strong word." and "the soul is but a manner of being--not a constant state--that any soul may be yours, if you find and follow its undulations (this is quoted from Nabokov).
Entertaining and quick, I would recommend as a vacation or "beach read."