Well the whole thing is plastic except for the screws and brass threaded inserts, so it's fairly light (especially in comparison to the camera head itself). The rigidity and wider footprint of the new mount it is a major upgrade from the old velcro setup. I had been strapping credit cards in behind the old velcro mount to improve it a little, but the new one is solid all by itself. If you snake the cable around back and anchor it to the helmet, it doesn't shake at all.
I think the best part is that it clips on/off the strap in seconds with no fuss. Before, it took me a good 5 minutes to rig up the velcro strap perfectly, and then it was on all day.
The mount does have fixed pegs that set the angle of the camera in discrete increments, but it looks like they could be cut off if you wanted finer control. So far, straight ahead works fine for me.