Question for GoPro users...

I use the underwater housing.
The GoPro is good for what it is.  There are a lot of limitations.

ChrisM is the underwater photography expert, so maybe he'll weigh in.
Lot's of problems crop up when you're photographing underwater.
Light falls of quickly the deeper you go. The spectrum toward the longer wavelengths (toward red)
get filtered out before the ones towards blue.  That's why the colors wash out.

To get really good quality underwater you need to supplement the light with additional light sources.

The focal length of the GoPro camera is essentially at infinity at everything but the closest distances.  Any of the housings will affect the clarity of the image to some extent.

The underwater housing also interferes with the microphone.

I'm starting to use the GoPro on some of my commercial projects. It's good for an added angle b-roll ect.  The kids and I use it also to record some of our fishing trips.  Haven't edited any of that together yet.  The best thing about the GoPro is all of the rigging options for it.

To my mind, it's hard to make a video using the GoPro alone and have it be interesting.  Although that soundtrack you used on yours reminds me of Jeb Corliss' "Grinding the Crack" video. Outstanding use of the GoPro, although he used three I think rigged to his body and used other footage from different ground angles.