Highly recommended. One enhancement request. Rated 5 out of 5 stars

This is a wonderful Add-on. I would be lost without it!

One recommendation: provide a CANCEL or STOP! options on the popup dialog that asks where to store the output. Since the email has not gone out at that point, it would be nice to be able to stop the process there. I would use this feature most often when I realize I don't have an appropriate folder to store the messages. The need is to create an output folder and the resend. Now I have to either "send and try to cancel before it goes out", or store the orig and outbound messages in some staging folder and then move them after I create the necessary folder.

This review is for a previous version of the add-on (1.0.0). 

Unfortunately its not possible to implement a cancel option. Just select some folder. Afterwards the standard sent-popup appears where its possible to cancel the mail.