i love my gopro and i've used it on numerous occasions (skiing, hiking, survival, diving, whitewater kayaking, rockclimbing, vacation timelapse, filming my fish in my aquarium, etc...)
and on every instance it has surprised me, the missing LCD screen isn't a really big deal once you're used to the camera, also the dozen mounts available are a real blessing (helmetmount, handlebar mount, chestmount and tripod mount are a real blessing)
another very sweet addition is to use the tripod mount in combination with a multipurpose minipod!
i think the main advantages of the Gopro is it's multipurpose use, imagine every condition you can think of and chances are the gopro can film there!
(just look into the GoPro spaceballoon videos, they're amazing!)
it's also very rugged and spare parts are super easy to find!
main disadvantages are: ugly, and not very easy to control, takes a while to get the hang of it ...
i haven't used any other Helmetcams yet, so i can only tell you what i know from my gopro...
Belgium represent !
"The windows are vertical how am i going to poop on those?"-Killabees
"God isn't black, you fucking moron!"-Shibby
"I shit rainbows and sneeze glitter."-Arabian