Rated 5 out of 5 stars

works flawlessly, supports attachments, Owl folks are super responsive. I've no issues just had some questions. After using for 2 days, I paid the €10 instead of waiting till the end of the trial. Ben and team deserve to be rewarded for solving this business issue. Let's be honest, nobody is using Exchange for their personal life.
Note there is a spurious message in bottom left of Thunderbird saying "deleted N messages from Inbox". Don't worry about that, Owl temporarily creates an entry, downloads message and deletes that. Nothing is lost.

This review is for a previous version of the add-on (0.6.4.3). 

Thanks a lot. I am happy that you like Owl :-).