There is a 3-axis electronic gimbal that is attached via dampers to the airframe, it really is rock steady. The Phantom 3 Pro has a 4K camera that is 'made' by DJI and provides an end-to-end system. I believe it uses a Sony CCD and chipset but would imagine it's very similar to the GoPro, with a 9-element lens removing the former model's fish-eye effect.
A lot of effort seems to have gone into DJI's apps to run the whole show and it's very cool to review the flight on google maps during and after the event including an impressive telemetry dataset and stick inputs. The control system is all new and uses their Lightbridge technology to provide both the FPV video, at 720p, and the RC data over the same frequency, giving a much greater range for both.
It seems DJI is going into camera development whereas gopro are rumoured to be looking at launching their own drone sometime soon. It just means better, more affordable tech.
"A man who does not think for himself, does not think at all."