Since several other reviewers have already described the overall plot and the main themes of this book - what does it mean to be a person, what does it mean to be free vs. slave, etc. - I'm just going to concentrate on my observations of the individual elements of the book that intrigued me, rather than repeating those. So please read this review in conjunction with several others, so you get the whole picture.
Charles Stross has a habit of paying specific homage to previous generations of science fiction authors in his books - for example, to Cordwainer Smith in "Glasshouse" - and in this one, he specifically mentions Heinlein and Asimov. However, there are many more references in here than just ones to Heinlein's and Asimov's books, though those are the most obvious ones. Some of them will be references only readers who have read some of the body of literature from 30 to 50 years ago will get (or even older - how many people will read the line about a character with urea and acetate and remember the old idiomatic phrase about being full of piss and vinegar?); others may be references that only younger readers will get. (For example, right at the beginning, where some of the characters are described as bishojo and chibi forms - mostly, it's going to be the younger generation that automatically knows what those are, from manga and anime; old fogeys may have to go look it up on the intertubes, which interrupts the reading experience.) And sometimes the references are more trouble than they're worth - giving two of the characters seldom-used nicknames so that one fleeting Shakespeare reference can be thrown in. Nonetheless, it's fun to try and recognize all the sources that Stross is giving credit to.
Stross's characters are a mixed bag, as far as level of characterization goes. Sometimes it gets a bit confusing - which aliases are sibs of which others? Whose soul chip is in whose body now? Wait, are Domina and Granita related? In general, though, most of the avatars are identifiable enough to follow the plot. And some of the characters, even bit parts, are truly one-of-a-kind: Lindy the sex-crazed shipping pod, for example, and Bilbo the hobo, who may or may not be saner than he sounds, and Paris the hotel front desk.
Stross also has a way with words that can cause one to splort soda out of one's nose on occasion, such as the beginning of one chapter: "There can be few sights more out of place in a luxury hotel than an angry bald ogress in a ripped black gown who storms in through the service entrance and demands to talk to the management..."
There are many other small bits that all add up to fun - the passing Monty Python reference, the ring-tailed lemur who snores, calling someone Igor, Dr. Ecks, the parody of the Creation Museum (and the mocking of Intelligent Design/Creationism in general). There are probably a few I missed, since I haven't read nearly as great a percentage of the literature ever written as Stross obviously has. Also, speaking of literature, I note that as with most of Stross, this book has had excellent editing, and is almost entirely free of the spelling confusions and grammatical errors that plague most genre and popular fiction these days.
Family reading alert: even though, as many people have pointed out, the plot for this book is largely based on Heinlein's juveniles, this is most definitely not a kid's book or even young-adult; there's far more sex in it than even in Heinlein's later adult novels, and some of it is very kinky sex. Probably not for anyone too young to buy the book with their own charge card.
Summary: although there are flaws - moments where it's hard to tell the characters apart (which was also a flaw in later Heinlein), a few points where the character's actions were a bit of a non-sequiter - this is nonetheless a move-right-along, action-packed space opera, with a great deal of humor and wit.