As I am trying to find a viable solution for an exec who manages other people's calendars, I've come across at least 2 issues using CalDav and it's incorporation into Zimbra one 1 test users calendar. I am running 5.0.8. and on Mac OS 10.5 Leopard.
1. If I'm on a Mac running Leopard, and I change the reminder of an existing appointment within iCal (it is using CalDav), the web client entry of this same appointment will change the reminder time as well. The issue is that the Web Client entry will not pop up a reminder, but the iCal entry will.
2. The other issue I've noticed is that in iCal I can't use find a location to actually reserve a conference room or set the location correctly in a Calendar Entry. It doesn't register on the web client entry as having reserved a location for a meeting.