I agree, P4 is a good drone, but I don't recommend it due to the range issues, as you stated, just 1 mile. In my book 1 mile is unacceptable, I expect 2+miles from my DJI drones, same as my 2015 P3P craft gets. Hence, the P4 doesn't live up to my expectations, using the GL300C. I will say, I've gone over 3mi with my GL300C with Windsurfer, but that flight was in very rural desert environment. The normal behavior of GL300C is that it's very temperamental in the semi-suburban settings (not big city) where I live. The GL300C signal integrity isn't as solid, losing control signal often with 4000' range, which is unheard of with my P3P. In fact, I have NEVER lost a control signal with my P3P to trigger RTH. I have always lost video signal first, usually past 2miles. With P4 and GL300C I will usually lose control signal first. often at less than 1 mile, enabling auto RTH, which I loath. When I switched to the GL658A Inspire controller to fly my P4, that all changed. I'm now getting "normal" 2+mile range and when I lose signal, it's always the video signal first.
My Mavic does 2+ miles easy, which is amazing for such small antennas. I hear the
P4P does 2+ miles also, my next purchase.