With the advent of the new Retina Macbook Pros, the new Mac Pro almost here, and Dell announcing new so-called “4K” monitor models at affordable prices more Mac users are considering to get a 4K monitor. It promises a similar display sharpness as the native Retina Macbook Pro displays already offer.
This promise though has recently been discussed controversially (e.g. ATP) with keywords being Pixel Density, Screen Space, Retina Resolution, HiDPI Modes.
Here is my take.