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Everthing that I have read suggests that OSX server is simply OSX with some extra services and kernel features (just like Windows).


And just like any other Unix with a client/server release.

OS X Server adds some specific GUI tools to configure things like Postfix for mail, Jabber for a local iChat server and Samba for the windows shares. It also contains tools for remote monitoring XServe hardware, like fan status and such. Beyond that, it acts just like the OS X client for the most part.

For people who want a cheep office server though, it does work well. Licensing wise, an OS X Server beats the pants off Microsoft licensing fees for Windows Server. I'd also dare say it's easier for a non techie to get working then a Windows server, but also offers the benefit of using the same UNIX daemons that other servers use. That enables so much power to be unlocked as well. A local Mac shop migrated their mail server to OS X Server last year away from an old OS 9 product. In doing so, they were easily able to add in free spam protection into Postfix. Where as if they had been a Microsoft shop, they would have had to first worry about Exchange costs, then the costs of a spam plugin.