This just won the Hugo. I don't think it should have.
It's not that it's not a perfectly adequate take on two interesting subjects, namely, sci-fi TV shows and time travel. And, hey, let's not forget meeting yourself when you go back in time. Those particular sections did make me smile out loud, because Scalzi knows his genre and is screwing with it in a uniquely silly way.
But is it Hugo worthy? I mean Dune and A Canticle for Leibowitz won Hugos. Those books are towering achievements in the SF realm, and deserved one of the highest laudations for the genre. Scalzi's work can be that great - I'm thinking God Engines - but most of his work is adequate to good, and in this case, just plain silly. Should silly win the Hugo? (I realize this is a fan award, and that I also haven't read the other nominees.)
Frankly, the first 1/3 of the book was simply dull and boring for me, as our crew of protagonists works out what is happening to them. Something we already KNOW because we know what "redshirts" means in SF. I mean, truly. Geeks are geeks, man. We know what the term means because we invented it. Meaning that those first 100 pages or so are quite boring, unfortunately. The "get to the point" kind of boring. The remainder was entertaining - especially when they reached Earth - and the codas were adorable. A whole book of those codas would have worked well for me. They didn't make up for the rest of the book, though.