So really, ArtByte is the only coin that has a working platform for musicians and it went live a year ago or so. The other two are not developed yet.
This is wrong, Musicoin has been active since February 2017.
The last I checked Soundchain it was about the same as most music cryptos, talk about how they will help the artist, but no working model.
Musicoin is the only one that has consistently given rewards. Numerous people can vouch for the money they've made mining it. Musicians are uploading music. People are listening. It has also done some world firsts, like fully enabling the DJ mix. Actually a world's first.
https://steemit.com/music/@theharddata/the-world-s-first-blockchain-enabled-dj-mixArtbyte is good too. But Musicoin, for music, is better, and blows everything else out of the water right now.