Played with it a bit on my powershot S2 IS. Controlling it took some getting used to. The live histogram is pretty damn cool. Couldn't figure out the lightning detection/shutter release though.
It doesn't offer a whole lot that the G9 doesn't already have, but I've been playing with it for the ability to run scripts. I'm interested in expanding the G9's time-lapse abilities.
I copied files to my memory card, put in camera and it gave me a "load firmware?" screen when I switched it on... After that trying to figure it out was the hard part