I don't have experience with the GPH3 on any of the drones..
While the DJI camera COULD be better (with anything else in the world) I feel for the early stages it is and what not - it's comparable.
I was getting more at the distance. HD video feed over a much greater distance over my Phantom 2V+
However, here's two video samples. First video was this past June (2015). My video feed kept cutting out while I was flying around the tower, maybe 500' out at the furthest at times. This tower sits on top of a mountain with NOTHING around it (great camp experience). I experienced better video feed back to my remote/phone at my home in suburban neighborhood!
Any who here's video quality sample from the Phantom 2V+ vs the Phantom 3A (pre 2.7k video update) both shot at 1080p