I'm using it
So far, so good.
What I like to do is have all my music on my phone. I don't care about streaming because I mostly listen in the car. I just have tracks I like and stick it on Shuffle.
I currently have Napster, but the killer use for me is that ALL the purchased/ripped songs I have on my phone, PLUS any that I tag for offline listening on Apple Music appear seamlessly in one place, so I can shuffle between them without there being any difference. That is perfect for me. So I'll cancel Napster and keep this.