Leah: Apple Music needs collaborative playlists. The "share" function is fine, but working on playlists with friends is a fun option that is sorely missed here.
Susie: Rdio links the Mac and iPhone apps in a really smart way--when I'm listening on my Mac, I can control the playback with my iPhone, and vice versa. It's so weird to me that Apple Music doesn't do this, since Apple is all about passing tasks from one device to the other.
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