This is the follow up to John Scalzi's Old Man's War.
This time we find out a ton more about the Ghost Brigades and how they work and how they're different from the "regular" soldiers (who aren't really all that normal themselves). There's quite a bit about what kind of rights they have or should have. They're created people and on paper they have the same rights as more conventionally created folk, but in practice they're almost slaves. Doing what they're told because it's what they're supposed to do. How can they make decisions about what they want for their future if this one life is all they've ever known?
We also find out more about Jane and what's happened to her since the end of the last book. And there's the always slightly odd bits about the generals being teenagers because of the nature of who they are. (and I mean odd-good, not odd-bad)
The naming convention for the soldiers is another fun little game (at least I think it is) except the characters are aware of it so they talk about it some too, it isn't just the reader noticing this time.