Owning both phones, I can say that the iphone lags and when compared to the note 8, I notice it more.
Yes, if I just had the iphone, I may not notice it.
As I said, I enjoy my iphone x but anytime I pickup a note 8, I can't tell myself the iphone x screen is better, or even equal.
Same screen or not, different colors, whatever it is or isn't, the note 8 and S8 and S8 plus have better screens. Its just how it is.
A simple test is to use stock settings on a samsung phone and stock settings on an iphone and turn on netflix or even youtube. I can't see why someone would prefer to watch something on the iphone, just based on the video comparisons.
I feel thats a very fair test, because most phone owners just text, web scroll or watch videos.