Review on Lenovo Ultra Thin FreeSync DisplayPort 65FAGCC2US 28", 3840X2160P, 75, Tilt Adjustment, Anti-Glare Coating, Wall Mountable, ‎L28U-30, IPS by David Dober

This monitor has worked very well for 6 months. However, today I noticed a strange square smudge in the top left corner of the screen. I don't know what it is and how to fix it. I couldn't find a solution on the internet. If you need a high-end monitor for gaming, this might be a good option. But if the monitor is only needed for work, I would advise something cheaper and simpler. It will probably last longer than this.