"server version" is that they eliminated the restrictions on the machines.

Plus they no longer have the X-Serve... which means they had to make it possible for many machines to connect to others.

And Yes, some X-Serve machines are eligible for upgrade to Mountain Lion.

And Yes, things aren't going to south on you.

If you wait until it has to happen... you *WON'T* have the time for it then either, but then you'll be forced and all the good will will be gone, because the forums will be full of angst when *everyone* is forced to do it.

If you do it now... its still a common complaint/question in the forums, but at least nobody is super roaring pissed about the issue and posting in all caps and others aren't avoiding the question like the plague.

Your choice in the matter always. But sooner is better.