Im on my third 6s, now as i had to replace the first 2 due to various faults (clicking screen, faulty home button).
This one is flawless, however the screen uniformity is now far from optimal - unfortunately. The second 6s had a similar issue, but there it was hardly noticeable. Its always the same hassle - you just trade in one issue for another...
About 1/4 of the upper part of the display is dimmer/darker than the rest and there is a fingerprint-sized darker spot on the upper left part as well. So, when browsing webpages like google or macrumors for instance it can be spotted - the lower part of the screen is white whereas the top part is more like a light grey.
However, i couldnt spot this "pressure point blemish".
I really dont want to go through another exchange through my carrier and wait for the replacement, as i sold my 5s last week. I guess, as i planned on buying apple care+ anyway, i m going to ask for an express exchange in a few weeks or even months. It shouldnt be a problem with this kind of screen and an express exchange is always a fast and easy way to get a replacement.