If their displays are faulty, there will be a noticeable ghosting effect when a window is left in the same place for a long time and then moved somewhere else o

If their displays are faulty, there will be a noticeable ghosting effect when a window is left in the same place for a long time and then moved somewhere else on the screen. A faded "ghost window" will remain in its place. Another issue is stuck/bright pixels, there may be several bright white pixels that never change. If your friends aren't seeing noticeable problems though, there's nothing to warn them about. It's not that one display is inferior to the other in terms of color accuracy or brightness or quality. One display (I think it's the LG) has a noticeable ghosting and bright pixel problem in some cases.