I would consider myself a Mac OS X Server expert (not at all compared to other residents of this discussion web site, however) but I know very little about Windows Server. So I can't objectively compare & contrast the two.
What I can do, though, is outline a few reasons why I love OS X Server.
- Stable & Reliable. I can't say I have even had one close call regarding losing data or having to reformat due to any reason other than anything caused by my unbridled meddling with system files which I should be... 😉 (One caveat in my opinion though is upgrading between versions--make sure you always backup before doing so)
- Simple & Straightforward administration. The administration in OS X Server is pretty much a breeze. And it is straightforward because, for the most part, everything is where it seems logically that it should be. This is unlike Windows where you'll find that not everything is laid out in a fluid or logical manner.
- Easy setup. Depending on what you're planning on doing, setup can be incredibly simple. I personally can setup a server from scratch in less than 10 minutes after running through the setup assistant.
- Features. Like I said, I'm not a Windows expert and haven't researched for this, but I think I can safely say that the features in OS X are pretty well unmatched by Windows--as far as being pre-installed and ready-to-go. This includes the Application Server, Web Log Server, iChat Server, DNS, DHCP, Firewall, NAT, NetBoot, NFS, Open Directory, QuickTime Streaming, VPN, Software Update Server......... et. al.
- Scalable. You can fairly easily plug in additional servers into a central Open Directory on one server.
- Kerberos and OpenLDAP (as opposed to Active Directory in Windows).
- Apple Discussions provide for a great community and support resource 😉
If any part of this is inaccurate please correct me.
I have actually written an article comparing & contrasting the two clients (Mac vs. Windows) which you can read here:
http://www.difinitymedia.com/~bsmith/article.php?story=20051108221953262
Hope this helps!
Regards.