I have used my go pro Hero 3+ for just over a year now and love it for doing sports/Wet style video.
Here is a time lapse video of crossing from Anacortes to Mud Bay in the San Juans. Camera was suction cupped to the upper deck and set to take pictures every 5 seconds:
Here is another video from different angles using the Time Lapse and video functions while we cruised from Anacortes to La Conner
This video was taken underwater from our Dingy while cruising with a Super Pod of Dolphins. Amazing to see what was happening under the boat while we were zipping around.
the battery leaves much to be desired and I have 2 different batters and I could easily use a 3rd. It's great to get specific sport style shots but not a great camera for day to day use (ie birthdays and such).