Rated 1 out of 5 stars

BACK UP YOUR ADDRESS BOOK FIRST! Cannot recommend this one. After installation, I found bizarre duplicate entries in the local address book. Deleting them only made matters worse, so I uninstalled the extension and restored the address book from backup. Instead I'm using gContactSync (available in alpha on Mozilla Add-ons; latest development releases on external server).

This review is for a previous version of the add-on (0.6.20).