At this point, I'm subscribed to both, and I hate it.
Apple Music's personal library management is worth every penny, letting you mix uploaded, purchased, and streamed tracks and having all the granular control of the (bad interface, but very powerful) iTunes, and a very well laid out iOS app. Also the deep-OS integration with spotlight and Siri is awesome. Also I feel the audio quality is better (I know its 256 vs Spotify's 320, but it just sounds so much better, especially in songs with complex treble and tons of hi hats and scares and stuff. My theory is AAC is better than OGG for electronic music, both are set to only feed me the highest quality file).
But while Spotify falls short on library management, it shines in discovery. Spotify has infinitely better playlists (for EDM at least, the "supplied" playlists on both suck but Spotify has extensive user created content thats gold). Also Spotify connect is incredible, I can hand off my queue and play session from any device (a feature I'm flabbergasted apple music doesn't have with apples handoff), and I love that I can sign into my account on any computer and control it from my phone (especially with apple musics very odd 90 day limitation), great for playing music at work and parties.
If Spotify ever lets me upload my own tracks, and edit my tracks tags ill probably ditch apple music. If apple music lets me sign into my account on any machine as often as I want, and improves browsing user-generated content without having them in my contact book, ill probably ditch Spotify.
Also I would love for either of them to offer a hi-fi tier but I can only dream.
edit: also I HATE that Spotify's list view doesn't have album art. It's a small issue, that is pretty much a deal breaker for someone who is visual.