Cedar Beeposted an image about GoPro Handlebar Seatpost Mount on March 26, 2013
I used this on my commuter bike with the camera. The plastic snapped within 2 months of purchase (and that includes one month where the camera was being replaced under warranty so there was no load on the mount as I didn't have a camera). It failed at the last connecting piece closest to the camera (the piece that turns the camera to face forwards instead of sideways if you're mounting the camera on the handlebars and not the stem).
If you choose to buy this mount, make sure to attach a lanyard or string to the camera and to the bike so that you don't lose your expensive GoPro because of one dodgy piece of plastic.
I will be purchasing an alternative company's GoPro handlebar mount that will last longer than this piece of plastic.