I've always had a pretty good experience ordering books from ThriftBooks. You get what they advertise with respect to quality. They are also pretty fast in filling orders and getting the book to you. However, be careful of how you order, because they don't always let you make returns. Their policy is not clear about what they won't accept back--their site says something vague about "qualified returns" (obviously covering their backside). I got stuck with over $50 in books that I didn't want. So to summarize: buying books from them is good, but their after-sale customer service policies are not in your favor.