I have just tried the GoCoder on my iPad mini. I set it to 720P and 60fps, and also tried setting it to 30 fps, but the stream, and the recorded file on the wowza server is only around 12 - 13 fps, which makes it not very smooth.
If I change it to 640*360, then it records and stream in 30fps.
Is this because of the iPad mini does not have enough cpu power for 720P?
I do not have an iPhone 4 or 5 right now, so I can not test it with these.