I'm generally satisfied with MacOS X - it's software so it sucks, but for my purposes it generally sucks less than most anything else.
One area which I've recently discovered that greatly displeases me is the fact that it's pretty crap at doing NTP. My G5 at work had its clock skewed by something like 4 minutes - "oh noes!" one might say, but the fact is that accurate time is important to sysadmin stuff, *and I have it configured to sync time*.
I discovered that it would adjust time ok once I opened date and time settings, but that's a crap way to sync one's time. Turns out that it writes a crap ntp.conf, so it can't really help it, and apparently it'll clobber changes you make too, if you're not careful.
Herewith some bookmarks to help me on my crusade for better time in OS X:
utah.edu tells us about their configs, and offer a few hints for making life better for most too.
The NTP folks themselves are at least peripherally aware of troubles in Apple-land too.
I will post further if and when I solve this issue. I'm just happy that I don't run any OS X Server machines, since I really wonder if they do the same thing.