Honestly I've been thinking about moving to spotify, but the youtube ad-free premium has kept me on google play music because it's just not worth it to switch. But Google Play Music has not been updated in what feels like ages. And the iOS client is terrible (I only switched in the last 6 months).
Seems like they're getting ready to pull the plug. I subscribed in Oct 2016, and over that time I've saved $2/mo on equivalent music subscriptions and had youtube premium included (yeah yeah I know adblock or pihole or nextdns negates the value, but it's nice to be able to use the youtube client on my phone without needing to set up those solutions). Net value has been $83 though I've paid for it with a drastically sub par music experience (sharing is pointless, can't see what my friends listen to, playlist management is terrible).