Appeared last night when I settled into bed for reading. Gave me a popup and the option to turn it on. I don't use a cover on my Oasis2 so I see it for a sec before it comes out of sleep. And of course while its laying around. Haven't checked my Voyage or Oasis1 yet.
Its nice now that I have it. But its not something I would "need" to have. Its not a deal breaker. Only turn buttons are a deal breaker for me.
Pretty much all my books are from amazon though (purchased,library,KU), so it should work on all of mine.