I'll never forget the time I experienced what Amazon produced when a third of my class purchased my book through amazon. At the time, I was unaware that Amazon has their own in-house print on demand service. (I thought all my on-demand printed books were produced through my service / publisher.)
I asked one of my students for their book to look up something in class while wandering around the auditorium. What I saw blew me away.
The printed copy looked like one of those old xerox copy machines that were on its last legs. Blurred text. Some pages missing text.
I was LIVID! I called my publisher to complain. That's when I learned Amazon fulfills amazon.com orders through their own in-house printing service.
I couldn't get anywhere with Amazon regarding my complaint.
To my delight - my publisher offered to replace every poor copy - at no cost - to those who wanted one.
Not only does amazon rip-off authors concerning royalties - they provide a shabby print-on-demand product.