I was out at Starved Rock today (national park by where I live). I had my 6S, 6S Plus, and my Sony 20mp point and shoot with me. I snapped around 100 pics using all three and did some intentional comparison shots as well.
What I found once they were on the computer was that while the photos taken on the 6S and 6S Plus were very nice (and also non discernible in terms of quality difference between the two), neither could match the point and shoot. The quality was simply better on the Sony and once you began to zoom and crop, it was no longer even close.
I also did a side by side two minute video while walking the trails to test the EIS vs OIS of the 6S and 6S Plus. I am not sure what these people putting out the side by side videos are doing, because I could not replicate them. The video on the 6S was almost at all times as smooth as the 6S Plus. The electronic stabilization more than held its own vs the OIS on the 6S Plus.
End of the day, as most others say, the camera with you is the best camera. But, if you are able to plan ahead and know you are wanting the best shots possible, take a dedicated camera. Sure, the 6S and 6S Plus will get you those desired Facebook and instagram shots. But a dedicated point and shoot will be best for zooming, cropping, printing, and overall photo quality.