The Music Player jetAudio Plus is really a very good player with a lot of settings. He really has everything you expect from a useful player. Actually! Unfortunately, it is the app open but only under certain conditions. "You must be logged in Amazon App Store to run this app" is the important statement. Why opening the app is linked to an application to the App Store. For me, this player is thus almost unusable. On the one hand, one can not always log (eg holidays abroad), on the other hand I want to just do not always have to login. A great pity, because otherwise the player in my opinion is really very good.