I had mentioned above that I can scan and save artists, playlists, albums, etc. from the one on my lap, but the list is independent of any other device. When I checked my phone app and laptop app this morning, they both had the same saved playlists as the one I originally saved them to. But I wish they all would show what was currently playing and had the ability to save, skip, change, etc. what was playing on the other device.
As of right now I could not try Amazon Music if I wanted to.
Neither mconnect or Bubbleupnp offer Amazon Music as an option.
Being Ayre based streaming they are my only options for control app's.

If it gains traction I am sure it will be added to one or the other at some stage.
the great thing about spotify is its discovery algorithm--it's uncanny how accurate its recommendations are. amazon's is primitive in comparison, although i notice it gets a little better the more i listen to the app. also, whereas spotify has radio stations for every artist, amazon has very limited stations. amazon does sound better, but at the end of the trial period, it may come down to how hard i want to work at setting up my play queue.
speaking of which, is there a function on amazon which continues to play similar songs after a queue is finished?