I use the Ram Mount system for my digi camera, GPS, and the GoPro.
It Works well for me. I also use a small elastic cord as a safety tether. Like previously mentioned, I wish that I had one on my last GPS.
I cut a piece of plexi, drilled and threaded a 1/4-20 hole. This allows me to stick the GoPro mount to it and then screw the whole assembly to the Ram Mount.
Interestingly, I have no vibration problem at all on my Deuce. But, on a rented EG there was noticeable vibration. Changing the Ram Mount to the short 3" one made a big difference.
I also ordered the LCD back pack viewer, which comes with a new camera case. It's so much easier to see what's being recorded while it's mounted on the bike. Plus, I can now know for sure that I haven't fumble fingered those tiny little buttons.
BTW, if you use a 'skeleton case' you can then use the USB cord to power the GoPro and not worry about battery life.