Well if you wanted to hear how they sound, Doug Wimbish was playing one at NAMM.
https://www.youtube.com/watch?v=Fn57mzmLGzQ#t=135
And Here's him with Victor Wooten
https://www.youtube.com/watch?v=XTpioN2g7Bg
And yes I hate that bloody kid in the first video, too much young to have more talent than me.