The Last Colony is less about war, and more about the struggles of ordinary people trying to make a new life for themselves on a remote alien world, despite the machinations and secret plots of their own government and the threat of being wiped out by alien attack. It reminded me strongly of Allen Steele's excellent Coyote series, especially when (==small spoiler==) John Perry and Jane Sagan go sprinting off into the forest to rescue some of their colonists from ... whatever creatures are out there... I almost expected a boid to jump out at them!
It contains all the great plotting and wit you expect from Scalzi; the (==small spoiler==) convenient box of tricks that Hickory and Dickory turn up with looks like a little bit of a rushed job - there might have been other ways to rescue the colony from that attack that weren't so much of a rabbit-out-of-hat, but I'd have a hard job inventing one that runs smoothly. Really I'm just mentioning this so that I have something to comment on. Makes me feel a little less intimidated as I write my own stuff.
As for the Big Ideas behind the writing, I'll have to post about that another time. Got a few things to do now... bye.