Rated 4 out of 5 stars

Cardbook is really working nice. Much better than the SoGo-Connector.

The only problem I got so far is that if the "collect outgoing email" option is active, addresses are saved, even if they already are in the addressbook. I think it would be more useful to only collect new addresses.

This review is for a previous version of the add-on (9.8). 

oops this is a bug... I will investigate...

EDIT : this should be corrected in 10.2