Finally got 3.0.10beta - thanks to @fezzyness
The forward and rewind controls certainly seem much less laggy and way more responsive. Can we scratch this off the list now?
The FiiO music app's new theme is nice, but this probably wasn't the highest priority. Neutron player has a lot of functionality direct from the lock screen now, but the hardware buttons (continuous volume up/down, track forward/backward) don't work properly. I understand it must be difficult for FiiO to make all features work in 3rd party apps, which is why I'm still holding out hope for FiiO's own music app.
FiiO - if you're listening - all I want for Christmas is gapless playback in the FiiO music app on my X7!