go pro with the chest mount is a great setup. Couple of reasons not mentioned, When skiing trees and in brambly areas, its easy to actually get your camera ripped right off your helmt, the chest mount is safe and secure. The chest mount is stable, very little shaking around. Chest mount is where your body is heading, helmet mounts follow your head obviously, so when you are looking around or scanning a line the camera is not necesarily looking at where you are skiing.
Yeah, that chest mount also gives away when your banking/inclining too much.