Since I've been complaining about structure in a lot of recent reviews, I will note that this book had a beautifully executed structure. Events logically followed events, there were appropriate rises and falls in the action, foreshadowing was established without Here There Be Foreshadowing trumpets. Scalzi knows his craft.
Unfortunately, I found it impossible to suspend my disbelief enough to buy any of the worldbuilding, and the main character came across as a complete Gary Stu.
But the structure, man, that was pretty.