I have an rMBP. I had been running it at the largest supported resolution (1920x1200). I just downloaded SwitchResX and set it to 2880x1800.
It seems to work perfectly. Everything is smaller, but perfectly proportioned, and there don't appear to be any weird issues like with windows via bootcamp (which has some things small and others big).
My eyes are good, and this screen real-estate looks amazing so I'm going to give this a go for a few days.
After a few hours I've switched back to 1920x1200. I still love the huge native resolution, and will switch to it in certain circumstances, but for regular web-browsing, email, text writing, etc, it is more comfortable at 1920x1200.
When I'm developing in Xcode or for the web I will switch back to 2880x1800 to get maximum real-estate for many windows.
It seems to work perfectly. Everything is smaller, but perfectly proportioned, and there don't appear to be any weird issues like with windows via bootcamp (which has some things small and others big).
My eyes are good, and this screen real-estate looks amazing so I'm going to give this a go for a few days.