Very good, it does the job Rated 4 out of 5 stars

Very good, it does the job on all types of directories (IMAP, Local, etc).

Waiting for the release to include options for removing duplicates in Sent folders, which i know is not included on purpose.

Keep it up!

This review is for a previous version of the add-on (0.1.4). 

Fixed in 0.1.4 and later versions

Use the hidden

removedupes.mail.allowed_special_folders

preference to decide which special folders (Sent, Drafts etc.) may be searched for dupes rather than being ignored.