Ok, but why? Because it's called Apple Music, what? Where's the advantage, to you? I've literally never heard anyone say that the Apple Music app is better than Spotify.But at what cost? The only reason I use Spotify is because the offer the $4.99 deal that bundles Spotify and Hulu. Without that it would be Apple Music
Spotify has great playlists, great suggestions - I can't even begin to mention how many great tracks I've had suggested to me in the Discover Weekly playlist that I never in a million years would have found on my own. Tons of friggin awesome ambient and EDM from (to me!) totally obscure bands and artists and DJs.
Apple Music streams to Apple Watch. That's basically it as far as clear advantages go from what I can tell. But if you don't have a watch with LTE and attached subscription plan then that's pointless. Apple Music has a somewhat wider range of music on offer, but it's not exactly a dealbreaker. There's absolutely tons to listen to on Spotify as well, you'll basically never run out even if all you do is listen to music 24/7.
So ask yourself, what do you gain from giving your money to Apple, a greedy, hungry monolithic company which always - despite its professions to the opposite - always strives to do as little as possible, instead of your money benefitting its much much smaller competitor?
Competition is good. It's what drives innovation.