Like quite a few Indie authors I've enrolled my 3 books in the KDP Select programme and, like many others, I have mixed feelings about the scheme.
I think it is the best way for new authors to get their books 'seen' but the free giveaways must be having a knock-on effect in terms of sales, not only of new writers, but also established ones as well.
It is a brilliant marketing ploy by Amazon,though, in that it has boosted the sales of Kindles. Very few people I know own an alternative e-reader-in fact there's just one, who bought a Sony.
Will I stay with KDP? Well, I've already withdrawn Tabnit Gisgo so that it gives me a few more options re vendors and I'll see how the next few months go.
What Amazon has done, of course, is give thousands like me an opportunity to blow the digital dust from books on my desktop and get them out there.