I have used the P9 before, the camera is excellent, easily top 3 in colour reproduction and photo quality. But it has few drawbacks, the battery life is mediocre, and the charging speed slows down alot if the phone is active while your charging, i had a galaxy s5 back then..even that can charge at about normal speed while im using it. Video quality on the P9 is average for what you paid for. Though the phone is pretty darn fast in everything,though the camera app can lagg when opening it, as a heavy user myself of the p9 then, if you use it heavily, running thru the UI you would see alot of stuttering after the 2 months mark. My theory is probably the CPU probably getting throttled too quickly due to the heat. If your considering the P9, the honor 8 more bang for the buck bro, though the p9 has better speakers,and a slighty better screen ( not like most ppl can tell unless side to side). Regarding the S7 I cant comment, never owned any samsung devices after the Galaxy S5.  I hope this helps!