In the house I run an Intel Mac Mini with OS X, but in the shop I run to plain jane PCs with Ubuntu Linux and EMC2. I have started trying to get EMC2 to compile under OS X a couple of times but I really have too many projects going on to spend much time on it.
There has been a strong resistance on the part of the other developers to even considering the use of USB with EMC2. The problem is that USB has delays that are believed to be incompatible with realtime usage. Right now there is a fair amount of discussion going on concerning the possibility of implementing a RT ethernet connection.
I use VectorWorks 12.5 for my CAD and I write most of my gcode by hand, however, I do have a copy of NCPlot for converting DXF files to gcode (I run this under XP and Parallels).
Transport of gcode to the PCs is via thumbdrives.