Full review
I have always had a great experience at Amazon.com. Every time I have ever placed an order, the shipping has been SUPER quick, they have never overcharged me for shipping (usually I get the super saver shipping so that it's free if I spend more than $25) and my products always arrive in pristine condition.
My husband loves to shop there for used books and he has always had great luck with the secondary market sellers. So, even if Amazon does not carry the book, they will list the book so that other sellers can sell their used copies and I know he has found one or two out of print titles this way.
I've also created an account to sell items on Amazon and did fairly well with it. You really have to keep on top of your account and make sure you're shipping on time, etc., but it's a great way to make some easy cash if you have media items lying around.
I've just had an overall pleasant experience with Amazon and think that not only is it a great shopping site and retailer but I use them for reference on certain items as well. They're almost like the IMDB of books.