Never wait so long to write a review... I remember the basic intent of this book, but not the essentials. As a series, though, this is going to be a good one. Scalzi is joining the ranks of brave sci-fi writers who base their plot around a murder mystery. (In general, the joining of genres exponentially increases the difficulty of writing.)
The book holds to the three basic tenets of sci-fi mystery writing: complex science, convoluted plot, and fully-fleshed-out characters. (OK, that last one should be true for all genre writing.) That convoluted plot gets a little difficult to follow towards the end - since some of the characters are human minds in robot bodies and some are flesh-n-blood humans, you have to remember who is of what type to follow how the mystery works itself out. The science is fascinating, in thinking of a world that includes these different types of humans and how society has adapted (or not adapted) to them. In some ways, Scalzi has simplified this. Since the human minds can jump into robot bodies in remote parts of the world, I can't imagine the jarring effects of that aren't more of a societal concern.
The writing is, as usual, Scalzi's special blend of explanatory mixed with humor. He never dumbs things down for the reader, but he recognizes the need to interject humor so his books are not dull tomes. For me, I'd appreciate him dropping The Old Man's War universe (which he's rather beaten to death, so he may very well have) and starting anew with this world.