I wrote this on my blog and wanted to share.
Why do so many ( relatively ) unknown authors complain about Amazon KDP?
I have to agree with your post. KDP does give you a great opportunity to publish and promote your work, and their sales are much higher than with any other site. I've recently took two of my books off KDP Select and uploaded them to other book-selling sites. The sales are inconsequential as compared to the "borrows" I got from KDP Select's Lending Library. I'm actually thinking of signing my titles back up. Amazon helps you sell, where other sites only give you a place to showcase your work in the hope that someone stumbles upon it and is intrgued enough to want to purchase it, and how often does that happen when there are millions of books to choose from?
Speaking of KDP Select - I've got a book of poetry there :P