Greg - The Hero3 has an improved function menu and an additional power on indicator light...........it's much simpler than your Nikon.
I have a grudge with GoPro due to 4 camera's with audio issues that are manufacturing defects and they know it...........but I'll bet that due to marketing expenses and the number of units in the market they can't afford a recall.
My Hero3 had similar audio issues and I went straight to the guys I was previously battling with and ask them to explain this one..........didn't hear from them for over 3 weeks, then I received an email requesting I upload the just released firmware and let them know if it resolved the issues. It did based on limited testing. It's the best raw audio I've heard from one of their products. Will it last? I don't know.
Sadly, all said and done I still think they currently have the most versatile POV with the best combination of video and audio quality on the market.
Dale - this was the main audio test, music is from the truck stereo with the camera mounted in a skeleton case:
http://youtu.be/T8vhmoUNz-k