The UX is slow. It takes 5 seconds to add a song to my library now. Half the time images don't load - so I have a bunch of black squares with words underneath. Sometimes music just doesn't play. 5G/4G handoffs confuse it, forcing me to force quit and restart. The shuffle/repeat options are buried in a weird location. Should be right next to the play button. These are all relatively new problems (the last 6 months or so.)
I don't mind paying for software. But I'm not going to pay for half-baked efforts like Apple Music is quickly becoming, especially if the price keeps increasing.