Now it came for my testing of mailbox deletion and restores: I deleted a user from the Active Directory who also had a mailbox still connected to that account. To my surprise, I found that deleting the user also deleted the mailbox. The mailbox didn't go into the Disconnected Mailboxes section of Exchange. (If I had disconnected the mailbox before deleting the user, it would have. But in this case, it was still attached when I deleted the user.) However, when I restored the user via the AD Recyle Bin command in PowerShell, the mailbox automatically was restored as well. I was happy to see it was so simple. That's my second commendation.
I've mentioned two criticisms of and two commendations for the AD Recycle Bin in Windows Server 2008 R2. I'm excited to see how this tool develops by release time and with corresponding service packs. It is a keeper, no doubt. Do you agree? I'd like to hear your feedback and experiences as well.