Power Amp is pretty good, built in equalizer and even a Pre-Amp, but the zio can only handle so much before you get a crap sound or the bass drowns out everything else. I guess with some tweaking it can be great. I'm still playing with it though. As for video.... sorry don't have anything for that.
Almost forgot, power amp comes with an option to automatically start playing as soon as you plug in your headphones. This was a godsend for me, as it seemed to not start playing in mono like the stock player seems to like every other time you started it.