I have a dell U series monitor and an S series monitor, both 27" and both 4K. I had always thought that the people saying "ah, color caliberation is so important" were just snobs, but holy fuck color calibration is indeed important. White looks different between these monitors and that's distracting. I have an older, smaller, 2K U series - trying to decide if this S series 4K is worth the resolution bump, or if I should return it.