Before you cancel, why don't you try to compare the two volume matched and un-sigthed.
I have tried to do that, or should I say we have. My wife and I listened to the same tracks, as far as possible volume matched, streaming FLAC files from our CD collection over the LAN, Spotify Premium and Amazon Music Unlimited. Unfortunately, my wife isn't overly familiar with the setup, so I had to 'drive' the test while she listened to the music.
Now I think I can hear a difference but I am aware of things like confirmation bias and similar artefacts. She has better hearing than I do but tends to be less critical of sound quality. However, in that test she could hear a clear difference too. To us both, Amazon Music Unlimited HD and Ultra HD is indistinguishable from the FLAC files from our CDs. Spotify Premium was perceived as inferior to both. It is a shame, because the Amazon apps on both Windows desktop and Android are pretty awful, whereas the Spotify apps are pretty good. But, at the end of the day, you do not subscribe to a music streaming service for the quality of the apps.
Hopefully, Spotify will, one day, start their Spotify 'HiFi' service and make that available at a competitive price. But I understand that Spotify have been promising this service for some time. However, for me as an Amazon Prime subscriber, Spotify Premium would already be more expensive than Amazon. So Spotify would have to include CD quality streaming at, or around, the same price as the current Spotify Premium to be a good value proposition.