Foobar2000 is my goto until PA supports streams and because I had stuttering issues with opus over bluetooth. free only, no ads.
https://play.google.com/store/apps/details?id=com.foobar2000.foobar2000
While using Rocketplayer (since PA doesn't yet support opus) I found this nice feature where the album art is darkened and lyrics display on top of it.
Lollipop natively supports opus but Poweramp will not read them at all AFAIK, opus are in an ogg container with .opus extension. I cut my library size down by 30-40% by switching from AAC to opus but I'm having to use Rocketplayer atm