Quite complicated compared to Spotify. The interface looks pretty nice and stuff is neatly arranged, but it's so complex. I don't know why they keep going with that jarring magenta/white theme though.
For music discovery, it doesn't hold a candle against Spotify. With Spotify I can listen to an artist, go to related artists, just tap and hold a related artist and quickly preview their catalog. When I let go with my finger I'm back to where I was. Apple Music feels like it's useful if you already know what you're looking for. The "for you" tab also seems pretty static as if it's basing my taste on the top 3 artists within the genre, whereas Spotify gives me new and widely varying content every day, and as soon as I listen through one suggestion.
And on a final usability note, Spotify can control my phone from my Mac or vice versa. Insanely useful feature, and no separate remote apps or setups needed. It's just there.
I don't see the appeal, I'm afraid. Having a large catalog is just not enough, and Spotify knows that.