It's always been challenging for me to administer a server running any Mac Server products. They've made so many tweaks to do things slightly different that everywhere else, it became quite difficult to troubleshoot.
Ran a couple of Xserves a while ago to run web application stacks on it and most of the time I diverged from using the GUI to administer things I shot myself in the foot (Apache, firewalls, initscripts, networking etc.).
The nice hardware - those CPU load meters were gorgeous - unfortunately doesn't make up for those problems so I switched back to non Apple hardware + Linux and never looked back.
Don't fight the system is a nice mantra to follow when using Mac OS X Server and that's not hard when you use it to administer a collection of other Macs & the network they're on or when using the built-in services without wanting to tweak/upgrade the versions yourself (iCal server, Mail server etc.).
This is something you hopefully learned early or were told by an more experienced Mac admin— configuring, let alone automating, Xserves from a CLI is an exercise in futility as so many components system have been rewritten to do things "the Apple Way."
Now that they have killed Xserve, where does that leave Mac OS X Server? Is it dead? Will they continue to develop it and for what purpose?
I was quite excited about the Mac Mini Server. The thought of picking up a box for my home that I could use for just about everything and integrates so well with all my existing hardware and software (Macbook Pro, iMac, iPad, iPhone, iTunes, etc) sounded awesome! And was so quiet, small, and even attractive enough to just throw under the TV to use as a media hub.