Ive had a couple of helmet-mounted cameras before getting the Contour camera and the mounts have always been "tempramental" to say the best. From the picture on Amazon, this one didn't look too convincing either but I gave it a go and I'm glad that I did.
Unlike a lot of other mounts, which use a combination of velcro and glue, this one uses two fabric "tapes" with snap-lock fasteners. The tapes are of generous length which means that they are highly adaptable to whatever the vent-spacing on your helmet happens to be. Fitting them is easy, loop the tapes through the vents, run them through the plastic snap-locks and clicp them tight. Stability of the camera comes from cinching the tapes up nice and tight, which the snap-lock connectors make easy work of. Using the tapes to mount also means that it's easy to get the lens positioned just how you want it on the helmet - central or to one side - just by adjusting the tape lengths.
Once mouinted there's even some fine-tuning of the camera angle built into the mount, allowing a few degrees of up/down tilt.
The mount uses Contour's "TRail" system which provides for an extremely secure atttachment of the camera to the mount itself - in fact I'd recommend putting the camera on the mount before attaching the mount to your helmet. Likewise, unmount the whole setup from the helmet before trying to remove the camera - the TRail system keeps a tight hold of tings. So far the vented helmet mount has held firm and provided great footage from some seriously bumpy mountain bike riding without budging, including hits from branches etc.
This is easily the best helmet mounting platform I've come across for cycling helmets so far and a great option for your Contour camera. Highly recommended.