People buy iPhone just for the purpose of "Show-off" especially to girls, that you are rich.
One misconception is iPhones don't hang, it is wrong; it also hangs like android. It depends on how one maintains the mobile (apps, cleaning-up cache, etc).
Another misconception is iPhone has better camera. Wrong. There are articles in web (anandtech) comparing the high-end smartphones cameras. You can see the same photos shot using different mobiles and decide for yourself. I'm not saying its bad, but it is not the best either.
For the price of buying ONE iPhone, one can buy TWO android mobiles with TWICE the technical specs of that iPhone.
Coming to the OP question, between iPhone 6s and 7, newer is better anytime. My friends say the new iPhone 7 is having bad battery, can't even stand till evening. Consider the 7 Plus model which has more battery, if you really consider buying. GL