GoPro is one of those brand names like Hoover that has become shorthand for an entire category of products and has even, like Google, spawned its own verb - to GoPro it.
How has it become so ubiquitous? Well, there really is nothing better when it comes to capturing the action whatever crazy activity or sport you're doing. These cameras are small, tough and give great picture quality.
The Hero 4 Black camera is "the most advanced GoPro yet". It's not cheap, but it's worth it.