I had never read any of John Scalzi before so I was coming to this work quite fresh. The blurb for the book sounded wonderful - one of my favourite scenes from Galaxy Quest is when the one guy realizes he's wearing a red shirt. There is also a Canadian comedy troupe that does a Star Trek spoof and the funniest line is "I'm the expendable crew member sir!".
Therefore reading a book where the people walking the hallways of the space ship start to realize that they are the redshirts sounded like a great book.
And I was not disappointed. The writing was great and the humour in the crew members disappearing whenever a major character started to show up never failed to crack me up. The three Codas were a wonderful ending to the book. I gave it 4-1/2 stars just because the characters' ability to convince everyone that they were from a parallel universe was a bit too easy, i.e. it stretched the disbelief requirements just a bit too much.