Spotify wins. Easily: Spotify's app is faster and easier to use on both PC, Mac and iOS (and probably Android). And more importantly, Spotify natively scrobbles to Last.fm on both PC, Mac and iOS (and probably Android).
Only pro Apple Music has is that they have some artists that Spotify doesn't (Taylor Swift...), which doesn't even come close to the benefit Spotify has with native scrobbling.
I had almost forgotten Apple Music existed outside of the Apple circlejerk, until I heard on radio today:
You can find our playlists on Spotify and Apple Music
It was eye opening to me.
I haven't heard of anyone outside of the Apple circlejerk use it. I don't think I have ever heard someone mention Apple Music in real life.
But since this radio station maintains their playlist on there, I guess it's somewhat popular here in Sweden.