I think I would check with your chain of command before I'd drop three bills on a helmet cam. The ONLY guys I've seen use them here in RC East is PAO types, and that for official release only. When they used them on a dismount patrol with us, they were constantly fumbling around with them, not watching where they were stepping or aware of what was going on around them. Our Platoon Sergeant finally told one guy to take it off, as he was holding up our column.
GoPros are good. If youre going to record with or without permission, dont be stupid. Really dont be stupid. Dont violate anyone elses privacy, dont video tape anything that will present anyone in a bad light, including the organization you work for, dont record anything that will give away plans, location, mission, etc.
Last but not least, do not lend or loan your camera, do not copy or distribute what you record, and maintain total control of what you video tape. If its a safe video and you want to show someone, you play it for them, on your only DVD copy, on your dvd player, in your home, and they do not borrow it.