Really great book (and series). Though it's not "hard sci-fi" by any means, the technology feels real enough to keep my brain from focusing on the holes and enjoy the fun philosophical and ethical problems that Scalzi comes up with
IIRC, it started out as a reimagining of Space Cadet by Heinlein but instead of the young it was with the old.
After the first book, he then goes to explore all the questions that it brought up. The question of identity (to me) seems like the most reoccurring question.
Btw, there's a new book in the series. The Shattering Peace was released in September.
