I've been using the line mount and the board mount form camrig for close to a year now.
You will get good results if you put the camera on the front lines just above where they come together. I have been tethering it to the ring so it doesn't slide up the lines and using plastic zip ties to secure the legs to the lines, but not so tight the safety line won't slide (4-line sle).
The ears on the waterproof gopro case are a weak point and will shear off in a big impact so you need another tether if you are going to abuse it, or you will lose it.
At this point you get a good pov of the rider and a bit of the surrounding environment,
so its worth the effort on a good day for sure!
The board mount which attaches to the fins on your board is another story-http://camrig.com/gopro/camera-mounts/gopro-fin-mount
This mount takes those ears totally out of the equation and can take a severe beating over and over again. Its the only mount I trust 100%.
I did a mod on this mount and put it on a strut.
The angle is perfect for pointing right at the rider and after 3 sessions I'm feeling pretty stoked with it. You really get a sense of the surrounding at this pov.http://youtu.be/3Fr1pUvmh_Y
have fun you guys and post it man!