Rated 5 out of 5 stars

Excellent work done.

Works fast. Even faster than the web interface :-)

Attachments are being successfully attached to archived Emails.

Too bad that there isn't a 'pro' version like in Outlook, that allows for 20$ per year to add contacts directly into Sugar.

This review is for a previous version of the add-on (1.4.9). 

The add on you're looking for is here: https://addons.mozilla.org/en-US/thunderbird/addon/opacus-sugarcrm-thunderbird/ :)