I like Elisa but when I try to organize my albums it always have some problem like, for example, sorting stuff in the right order. A nice UI and a decent Plasma integration are welcomed.
[edit] At the end I'm still on Elisa since it's the player I prefer, I hope they'll add some sorting options (such as original year album).
Strawberry Music Player. Be sure to compile for QT5 if you're on KDE5.