Same here.
Tired most of them and go back to Poweramp every time.
Shame because I do like the Google play music app but Poweramps equalizer owns all IMHO.
Just another note. I use the music manager tool at home to point to my iTunes library, so Google Play always had all my music listed. So much easier than transferring music over. One more is that the Google Play Music app on my Nexus 7 2013 does have an equalizer. It also has gapless playback.