I have been a long time Spotify subscriber but gave Apple Music a nudge when it first came out.  Have since cancelled Apple Music (at the end of the free trial) and stuck with Spotify.

The single biggest advantage that Spotify has for me is Spotify Connect.  This gives me the ability to control Spotify on my HTPC (connected to my hifi system) from my phone and tablet.  It even allows me to control Spotify on my phone docked to my bedroom stereo from my tablet.  I use Spotify Connect all the time.