Google Play Music is the best deal out there - ad-free Youtube TV is bundled in the plan and allows you to upload your own music that you can stream from anywhere. That said, it's the absolute worst in terms of UI and cross platform support. I kept switching between subscriptions because Spotify still doesn't allow uploads (which I really need). But gave up on everyone and decided to just sync my personal music to my phone and use Spotify. The Discover Weekly and other playlists combined with a really solid cross-platform support I'm not moving to anything else. I have a windows computer, an xbox one, iPhone, Alexa, a Macbook and chromecast and Spotify works on every one of them. No one's ever going to beat that.
That said, I'd very skeptical of investing in Spotify. Apple Music has a real chance of becoming the default service everyone subscribes to on their iPhone without thinking twice. Apple Music just have to be good enough.