Rated 4 out of 5 stars

We've been using this for more than a year now, and it works like a charm. Android devices, Gmail webmail usage and Thunderbird.

Only thing missing is support for contact groups in Thunderbird itself, e.g. in Collected Emails etc. but that is hardly the plugin that must provide that feature.

This review is for a previous version of the add-on (0.6.40).