I have been putting together a DJi s900 drone which makes use of the fantastic Panasonic GH4. The video capabilities of this camera are astonishing in good light and can also be filmed in native 4k. The video below is a mix of Phantom and GoPro Hero3 footage and the Dji S900 and GH4. I would loved to have created this in full 4k but it has been downscaled to 1080p due to the limitations of the Hero 3. (Hoping a Hero 4 will be on the cards soon)
The image above is actuall a screengrab from the 4k footage, and I am amazed by the quality.