Yeah, they are good and a bargain all round, I now have the p30 pro, which is also great.the P20 Pro has a great camera and processing. It looks much nicer than my iPhone XR on the same scene. The AI in the P20 Pro is quite smart and adapt to what it thinks you are looking at and process the colours accordingly.
I got rid of my iPhone 5 for an S7 Edge because of the camera on it. Never noticed over-exposure. Had it 4 years and still love it. Had some of my best pics off it. Might have to change it because of the battery (3600 mah down to 2500 )I would rule out an S7. My one clearly overexposes. Photos from my iphone SE look much better