Normally, I’m all for subscription services, but I’m unimpressed with Kindle Unlimited for a couple of reasons.
As a reader, it doesn’t impress me because a great many of the books I want to read won’t be available. That’s the fault of big publishers, who won’t put their books in the program. As a writer, I am NOT going to sign a contract to sell my books exclusively with Amazon. I want my books in as many venues as possible.
Hmmm… I wonder if Amazon is demanding that the big publishers sell exclusively with them, and that’s why the publishers won’t enroll their books?
Marlene Dotterer 
I’m with you on this. The biggest red flag for me is offering it only to those who are in KDP Select, and I’m not a big fan of that service either.
I would have liked to enroll, but I won’t do it if it means I have to take my book down from B&N, iBooks, etc.