I recently needed to restore messages located in a user's Sent Items & Deleted Items folders from several month-end backups. Although the messages did restore, I noticed two issues:
1) somewhat annoying: when displaying the user's folder list, the number of messages in each folder and the folder size displayed corresponds to the number of messages and folder size from the last backup performed, and not from the time at which the backup being restored was performed.
2) very annoying: when restoring messages, duplicate emails are created and there's no option to exclude duplicates. To make things worse, if you use Outlook to export to a .pst file and then reimport using Outlook and selecting the option to ignore duplicates, the dups are created anyway. It seems that somehow Barracuda is restoring the messages in a way that Exchange & Outlook think they are not dups even though they are dups. When I was done restoring, because of the large number of duplicate emails, the user's mailbox grew from 2 GB to 36GB!