IMO a piezo into the right gear (t c electronic bodyrez for example) then straight to the board or an acoustic amp is a great option live, and better than a badly amped real acoustic. Of course if I was playing an acoustic gig I'd rather play an actual acoustic! Too many people judge piezos...
I have a UV7 that for some reason was always a little lifeless. I went for slightly modified Painkillers and couldn't be happier. The stock Painkiller will get you where you want to be.
I'm a long time lurker here! Thought you might be interested in my version of this install, posted over on Jemsite: http://www.jemsite.com/forums/showthread.php?t=68449