This Christmas present has a fun little plot: The protogonists are low-level crew on a Star Trek-like ship. They notice their number are dying far too frequently on away missions, and eventually realise they're in a sci-fi series! Such a book allows for both some tension and a great degree of humour, that Scalzi pulls off nicely.
With such a reflexive plot, I felt there was a danger of it getting a bit meta. As the main plot was resolving about three-quarters of the way through the book, I feared a particularly laboured and drawn-out twist. It didn't. It turned out the rest of the book was three entertaining little codas, providing nice extras to what would otherwise have been a fairly short book.
It's entertaining, it's written by a decent author, it's not particularly challenging, but it's very fun. It's a great present. Thanks, Jude!