Both the phones have their pros and cons, I think you should go for Samsung Galaxy J7 Pro.
Samsung Galaxy J7 Pro has the following advantages over iPhone 6S: -
1. Samsung Galaxy J7 Pro has 5.5" display size while iPhone 6S has 4.7" display size.
2. Samsung Galaxy J7 Pro has 13MP Main Camera while iPhone 6S has a 12MP Main camera.
3. The display of Samsung GalaxyJ7 Pro is Full HD while iPhone 6S has an HD screen, would matter when viewing high-quality movies or playing HD games.
It is not like that it is a one sided game, iPhone 6S has the following advantages -
1.iPhone 6S has 1.85GHz Dual Core Processor while Samsung Galaxy J7 Pro has 1.6GHz Octa Core Processor.
Verdict - In my opinion, Samsung Galaxy J7 Pro is a better phone in overall performance but if you need a phone with good front camera for taking selfies, you can go for iPhone 6S.
You can also compare these devices on 91mobiles. Link - iPhone 6S vs Galaxy J7 Pro
MD AMIRUDDIN ANSARI