Here is an example of a GH4 video that I've just finished editing: http://www.peterwalker.com/komodo.html
It demonstrates the camera's capabilities both WA (7-14mm lens with Zen 170mm dome), Macro (14-45mm PZ plus flip Subsee +5 dioptre) and above water (12-35mm plus polarising filter). I did all the editing in 4K and then compressed to 1080P just before uploading to Vimeo.
It was a pleasure to shoot and edit!
Thanks to David Cheung of ScubaCam for helping put the equipment together for me.