The sound quality is better, and you have different music available.
The app itself, though, is not that great. It's slow and inconsistent.
Moreover, if we're looking at the content itself, if you like some niche or more specific genres, you're out of luck. The music is there, but your only hope to find more of it is relying on public playlists created by the community.
I really do hope that Spotify nails it with its Hi-fi sub. The difference in sound quality is very noticeable to me.
Sound quality is better, artist are getting pay more and I have more music available(Joanna newsom, skeemask)