The odd thing for me is that I always thought that this book was satire in itself - I hadn't realised that Heinlein actually meant for a number of the themes of this book to be taken literally. That explains why the movie (which I just recently saw) struck me as an entertainingly over the top emphasis of the satire I saw in the book, while many Heinlein fans thought it was naught but sacrilege.
At any rate, it's certainly an excellent book - I quite enjoyed reading it.