Just started playing again and was very happy to see there is a Mac client now.
Installed and updated and in every way runs faster and looks great. I get better performance and graphics than on the PC version. All the functionality is the same as the PC client so I was able to just install and start playing right away!
Only issue is whether running full screen or windowed, I can't change the brightness or gamma. I change the sliders, but there is no effect and even when in a brightly lit wilderness area things are a bit dark.
This is on a 2011 Mac Book Pro dual boot OSX/Win8 btw.