Viper or Poweramp

I'm on Cloudy G2 3.3 and I'm wondering if Viper equalizer is any better than Poweramp or Musicmatch.

I have Poweramp and Musicmatchx and these days I rotate between these too, but seems like Musicmatch feels better audio wise and power amp UI wise.

Grant access problem with poweramp?

I'm using an lg g4 and I'm on Android 5.1. I want poweramp to be able to delete songs off the SD card. When I try to do this is says I need to grant access. I give it access, but after that it still doesn't work, it asks me to do it again. How can I fix this?