The finale to his "Old Man's War" trilogy, I found this a bit of a let down. The whole series was fun but not challenging, but I'd been lead to believe it might go a little beyond basic military sci-fi here. It's not a bad book, it's still a good page turner, but there's nothing to pull it out of a mediocre genre.
The first half of the book is pretty much a straight-forward story of colonisation, and is pretty dull, except for the snippets of political set-up for the second part. The later part does have some twists going on, which I'd best not spoil, but suffice to say there is some military action, which is a relieft after the tedium of the first half. The political part is surprisingly weak, mostly relying on the Heinleinesque technique of making sure that the 'baddies' do something increidbly stupid to allow the 'goodies' to show their superiority. Yay. On the other hand, at least Scalzi has no political axe to grind, so it remains good lightweight fun.