I noticed from this post that there is (or was) a problem synchronizing calendars with Entourage -- here's the quote from a Zimbra document I haven't been able to track down:
Note: Appointments in the ZCS Calendar will not be visible from Entourage. Since meeting invitations sent to ZCS users will create appointments in the ZCS Calendar, Zimbra recommends using Entourage calendar only for personal calendaring at this time (i.e. creating personal appointment without inviting others.) Zimbra is working on solutions to resolve this in the future.(Emph added)
This is dated March 6 '06.
I interpreted this as meaning that you effectively can't sync appointments that are created via meeting notice. Is this accurate, and if so, is it still true?
If so, it kind of takes Zimbra out of the running (versus Exchange) Entourage shops -- if you actually want to use any of the Exchange-like features, that is.