I recently subscribed to Apple Music, and it hasn't been fun so far.
I'm currently trying to figure out why I only seem to Sync from my iPhone to iTunes, and not the other way. Not consistently anyways.
If I download an album on my phone, it shows up in iTunes. However, if I create and manage playlists in iTunes, those changes are not reflected on my phone. When I first went live with Apple Music, my playlists were copied to the phone, but dupicated. It was a mess.
I've ensured that I have iCloud sync turned on in both devices, and something must be right for the computer to be aware of new tracks on the phone.
Here's some more background.
I had over two hundred thousand songs in my iTunes library before subscribing to Apple Music. I let the iTunes library churn on my computer for about 2 weeks, and it still was practically unresponsive and said it was still working on updating Apple Music and iCloud. I finally grew tired of it. I know there is a match limit of one hundred thousand songs, so perhaps that was my issue. I decided to delete all music in my iTunes library and start fresh. Because I have a pre Apple Music backup, I can add back in items I will not be able to get from Apple Music.
At least I hope I can. If I can't create a playlist in iTunes and have it sync to my phone, I will lose mobile access to personal recordings.