Review for gContactSync by Kyrandita
Rated 4 out of 5 stars
Very useful, Simple and concise, works almost exactly as advertised. Except for a few small issues, a great add-on, much easier to use than other gmail syncs I've tried.
Small suggestion to first-time users of this add-on:
export your contact list from google into the google.csv BEFORE trying this out... while mine and many other peoples experiences have been for the better there is always the chance that some conflict will arise with another of your add-ons, Just to be safe :)
To create your own collections, you must have a Mozilla Add-ons account.