I used Google Music for streaming music ever since it became available in our country. I remember the first thing I did was to back up all my mp3s, but after that I used to stream many other songs and that worked just fine. I found everything that I was interested in on there.
At least for me it was a good music streaming service, had all I ever needed.
Now I switched to YT Music. Not sure how that's any different. It still plays most of the music I had bundled up in the playlists I created over the years and that's fine I guess. It seems a bit easier to find live sets from festivals with YT Music so that's a plus.