I'm in the same boat. I actually even have a gpm/ytr subscription paid through 2019 already (I bought a ton of $5/mo coupons and redeemed them all).
Despite that, I'm thinking about getting a spotify sub anyway. The music discovery and especially the user playlists I find to be far superior. GPM is really lacking hard on the social front.
You can do all that with a free account. In fact, just get Stamp to move your Google content to spotify and you can use it all free without even playing songs in Spotify. Its a little less perfect, but it gets the job done.
Despite that, I'm thinking about getting a spotify sub anyway. The music discovery and especially the user playlists I find to be far superior. GPM is really lacking hard on the social front.