The biggest drawback, and its fatal flaw, is how closely it mirrors Heinlein's Starship Troopers. And the odd thing is that the author knows and comments on this in his Acknowledgements, "Finally: Thank you, Robert A. Heinlein, for debts that have (since these acknowledgements are placed in the back of the book) become obvious."
Scalzi had all the elements for a vastly different and deeply engaging novel, had he just come up with his own plot, and fleshed out his characterizations and ideas in a little more depth. How much more effort would it have taken?
It is still an enjoyable story - a good appetizer for the imagination, as you think about what life would be like as a Colonial Defense Forces soldier, what type of civilization the CDF would foster, how its interactions with the other races seem to be very violent yet stagnant, and how those migrating from Earth would feel about their home world. The politics, the strategy, the ethics - all of the elements are potentially there for a first-rate novel of some length and depth, and the best the author was able to do was take his ideas and plug them into the same formula as Starship Troopers. Is this a homage to Heinlen's original novel?
Its hard to say, and hard to justify why I enjoyed this novel so much, despite the unimaginative use of Heinlein's formula (right down to the weak, vague ending). The elements, I suppose, really fired off my imagination as I was reading it, and the main character's dry sense of humor appealed to me more than Heinlein's - these two things make it a good read, whereas it could have - with some work - become a great read.
