Official comment
The will be referenced almost identically. They say that the Phantom 4 has a more accurate GPS but we haven't really see that as being the case. At does however have redundant IMUs in the case of a failure which is nice. The cameras are pretty much the same electronically. The optics on the P4 are supposed to be better but we don't really see evidence of that in our finished products. If you want to make a just in detail and quality you should look at the X5 camera.