freitasm:
Qobuz has great HD sound but doesn't work with Amazon Echo (if that's your thing). If you have a phone and headphones that support HD / LDAC then you get great sound.
Amazon Music is great, works on smartphones and computers, integrates well with Amazon Echo devices and has a higher sound quality than Spotify.
Then there's Spotify, which works with Amazon Echo devices but has a lower sound resolution.
Just to clarify - Spotify doesn't currently use a lossless codec like FLAC
It does however use 320kb AAC which is still a very good quality codec and 90% of people are not going to recognise any quality issues.
You can choose to use lower quality codecs in order to save on data (if on a mobile connection for example)