Couple of issues with ZCS 7.0 Mobile-/ActiveSync'ed HTC Desire:
1) It only syncs the main calendar, not any secondary calendars I've created at all.
2) It only syncs contacts from the main contact book, not secondary contact books or even contact groups, and probably not shared contact books either.
I am aware of the app 'LVContacts Sync for Zimbra', which works fairly well, but I don't really like having to tell our users that they'll have to pay for a third party app to get functionality that ought to be there out of the box.
Other than that I am really very happy with how well this works