We have a few users who have taken the plunge and migrated to both Windows Vista and Office 2007 (With Version 5 of the Connector). They have been plagued with issues since they made this jump and I'm not sure what, exactly, is wrong.
Issue 1: E-mails will, without warning, sometimes get stuck in the Outbox. E-mails can be as small as 5k without an attachment of any kind and others can have a 21 Meg attachment. (Our limit is 32MB.) There appears to be no pattern. Might this have something to do with our Anti-Virus software? One user has AVG 8.0 on his PC and another uses Norton Internet Security. Disabling Web and E-mail scanning has mostly resolved this issue on the AVG machine, but not on the Norton machine. We've had to move him to the Web Client while we work this out.
Issue 2: Without reason, some e-mails will leave the Outbox and go to the sent folder, but a message will be returned almost immediately from Zimbra with a HUGE line of error codes and an HTTP Error 500 - Internal Server Error message. The majority of the error messages have to do with the Jetty Server.
Issue 3: Outlook is, at random, switching to Offline Mode. The problem can be fixed by simply de-selecting the option in Outlook, but it sometimes happens several times a day.
Issue 4. The GAL becomes unsynced or lost. Without reason, the GAL and Calendar for a particular user will become either unsynced with changes I've made or just flat out NOT there. This can be remedied by a complete cleanout of Application folders on the computer and a full re-sync, but this is very time consuming.