The UI is the worst I've seen on any music service or player, but I'd found quite a bit of music I like through their recommendations.
I used to pay for Google Music and transitioned to YouTube Music but eventually gave up because it has so many issues. I also tried Spotify but didn't like it much so now I don't know what I will use.
The implementation and mixing music videos with other video content in my Youtube account is horrible on the other way.
Youtube Music implementation of Chromecast is spotless while Spotify every so often interupts with "Your spotify account is used on another device" (Not true just checking my phone). In general Youtube is also tolerant of using two devices with the same account for a few moments.
And no podcasts in the music app... Hurah...
I gave up on Spotify when they removed the widget functionality on Android. I know they returned it eventually, but not without complete uproar. It burned myself as a decade old (family) premium user though; I used to love them, but that complete disregard completely changed that.
Now, only a 3 month minimum (6 would help) completely free retrial would get me back. Thus far, none has been received.
(On the flip side I absolutely love YouTube Red or Premium or whatever they call it these days.)