I was in Cozumel a few weeks ago, doing some diving obviously, and shot a little bit of video.
If you're interested, here's a 9 minute highlight clip from the first few dives. This video was shot with a low end "GoPro clone" camera that cost about $30. The video quality isn't bad for a $30 camera, but doesn't compare to a normal GoPro. I wanted to try it out underwater.
I'm making a second highlight reel, using only video from a real GoPro. I should have it done in a week or three. Things are busy at the moment.