I've been using Google Play Music for years now, although it wasn't my only music app until the Songza acquisition in ~2014, its now become the only thing I listen to, except for the occasional XM radio in the car when I'm bored. The YouTube Red thing seemed useless at first, but I've found myself consuming more YouTube content these days, and while I wouldn't pay for it on its own, as an add on feature its pretty useful.

At this point there is no way I'd go back to listening to music with ads in it, and unless google ruins it, I don't see any reason to even try to switch.