Spotify is a nonstarter for me because I can't upload my own music. I don't want to be beholden to whatever they decide I can listen to, and there's lots of music I want to listen to that's not in any streaming catalogue.
edit: note I say "upload," not syncing local files to my phone. I want a built-in streaming catalogue + cloud music locker that all my devices stream from, not something I have to manually transfer files between for every device