Camera differences:
Phantom P4: FOV 94° 20 mm (35 mm format equivalent) f/2.8
Mavic Pro: FOV 78.8° 28 mm (35 mm format equivalent) f/2.2
That's all I can see.
There is a question, though; will the Mavic do HDR or not? (I suspect that's a function of the DJI Go app, not hardware)
Phantom P4: FOV 94° 20 mm (35 mm format equivalent) f/2.8
Mavic Pro: FOV 78.8° 28 mm (35 mm format equivalent) f/2.2
That's all I can see.
There is a question, though; will the Mavic do HDR or not? (I suspect that's a function of the DJI Go app, not hardware)