MACs would be great for clients. I just don't know of any great server OS made by Apple.
I do think Jon would be able to expand his business if he wrote code for Apple.
I regularly use this Mac to talk to our managed environment - works fine. Of course, my dev-box talks to them as well, and it is a CENTOS6 box - it works fine as a client as well. And of course, AC is running on Windows, and that instance is in turn running on Linux environment.
For the most part, client OSs are pretty fungible these days. My dev-box has several different ones [XP, W7, UBU12, RHEL6, and room for several more], more than I typically get started at any one time. Have ISO, can boot and run.
