Bought a Tribord and used it twice at Diamond Reef - loved it. As stated, it's best for snorkeling in good conditions - they are a heavier mask than your standard issue and it is not a quick process to remove them. I can absolutely understand how they could be dangerous in rough conditions. It's not easy to "rest" them on your forehead the way you can with a regular mask. I really like mine, but I will keep my standard issue on hand as well....