Currently I'm working with 15'' rMBP and I have attached via Display Port an ASUS PB287Q 28-Inch Screen LED-Lit 4K Monitor at 3840x2160 HiDPI, everything looks "retina" to me. I'm contemplating on getting the new 5k iMac but I wonder rid I'll notice the difference at all from 4k HiDPI to 5K, I assume that tit will look better as the ASUS is a $500 for the new affordable 4k monitors released this year and Apple screen will look better because the components are better? I'm not sure about the color quality and the whites on the ASUS but it is not too bad, a big improvement from a non 4k monitors and everything is super sharp. I'm trying to avoid spending $3000 on something that will look exactly the same. I'll appreciate some guidance.