I would never use that large scaling on an iMac. Everything would get super crammed. I use the default 2560x1440x2. And for the record, my eyes are crap! In fact, I zoom in all the time, but I love the screen real estate still. More menu bar items, more space for windows side by side, more visible objects in apps like Final Cut. Besides, I think it just looks nicer in its default setting - everything seems to have the right proportions, especially with respect to the menu bar