I switched to a OnePlus 5 a couple of months ago from my L950 XL. I've used WP since inception and feel it's probably the only Android phone that comes close to the consistent performance of WP and has extra tidbits that make Android better, and the settings menu has a dark mode
As someone that's used MS music services since URGE in Windows Media Player, this news really disappoints me and I'm finding there is simply no direct alternative. Groove is no Zune, but it organizes and presents music the same, it's (mostly) consistent across devices, and the OneDrive streaming (which is remaining BTW) makes it so easy to get your personal music into your collection.
Anyway, I'm trying out Google Play Music with a 3-mo YouTube Red trial. It's not bad and it does work. However, the app is designed like the Google Play Store and doesn't really put "my music" front and center. The artist list in your library is ugly and when you click an artist it shows you tops songs (not your top, but the service), the artists albums in the store, and then what's in your library, even though you are browsing your library to begin with. Albums list is fine. Now playing cuts off the album art and some of it's not even high quality. I have to edit album genres, but there appears to be no way to do this or any metadata updates in bulk so that can get annoying. The major thing is that it has the music locker so I can upload and have my personal music so I'll see how it goes. Also, YouTube Red is a standout addition as well.
I already know I don't like Spotify for my needs, however it is a great service. I'll update how I feel about it.