Here's an opinion by a well known author on the 'tweaks' as to how KDP Select Authors will be paid for their books picked/read by readers in Amazon's Kindle Unlimited program.
Link: John Scalzi-- Amazon Tweaks Its Kindle Unlimited System. It Still Sucks For KDP Select Authors
|Two Popular Novels by John Scalzi|
I'm not involved in any way, as my publisher (Gryphonwood Press) doesn't restrict any works published by Gryphonwood to have availability only through Amazon. Also, as a reader, I am not part of Kindle Unlimited.
While the article/opinion mainly focuses on the effect on authors, how authors respond (or don't respond) will ultimately affect readers. For what it's worth, I think John Scalzi's views are pretty much on target, and I agree with the choice of my publisher to distribute through as many venues as possible.