I've produced and sold over 1.5 million DVD's on digital photography. I've personally owned over 145 cameras in the past 10 years, and that doesn't include any cell phone cameras.
I teach photography professionally. You can check out my youtube page
http://www.youtube.com/dbkcreative
Those are my credentials.
Here is my definitive statement on the iPhone vs GoPro debate.
THERE IS NO WAY THE iPHONE CAMERA IS BETTER THAN THE GOPRO IN IMAGE QUALITY!!!!!
First, the sensor in the GoPro is larger in physical size. It is the size of the sensor that matters most. You can check it out in the specs. I've seen each sensor in the RAW - in other words outside the cameras.
Second, the lens on the GoPro is superior to the iPhone. It has a better speed, and more actual glass in the make up of the construction.
Now, on the subject of compression, which is what your argument is based on. Take a look at the file sizes. The GoPro file size is larger. It has LESS compression, not more. The file that the iPhone makes is purpose built to be emailed using cellular data. It has the most compression of the two cameras. Neither takes a RAW file. RAW files only matter if the sensor is larger, and if you intend to modify the image. RAW files are like working with negatives.
Third, If you use the wifi networking on the iPhone or for that matter the GoPro while flying the Phantom, you can guarantee a flyaway. The two radios will interfere with each other. Read the threads carefully. There are lots of warnings from even DJI about it.
Lastly, there are purpose built accessories for the GoPro and your Phantom. Thing like gimbals, mounts, and even ND filters, which will improve your image.
If image quality is important, buy a bigger bird, and put a DSLR or APS-C sensor camera on it with a real lens. Of course, you are now in the thousands of $$.
I don't care what a photo finisher has to say on the matter. He doesn't even spend a second looking at the image. It's all done by the computer now.
I hope this helps.
Darren