I am using a Macbook Pro with Retina, and it is the best computer I have ever owned. My workflow is to do almost all my Lightroom editing on the Macbook Pro, then send the files to a Mac Mini, which uses a calibrated Spectraview monitor and large external hard drives. I find that color and most other variables are nearly always perfect, but sometimes I need to add contrast to the final DNG file. Apparently the Retina screen makes the file look more slightly more contrasty than it does on a calibrated monitor.
If I was just using the Macbook Pro with Retina, I might add a bit of extra contrast before printing. Overall, it is nearly perfect.