Review for gContactSync by Ray Turner
Rated 5 out of 5 stars
Works like a champ!
Fills a giant hole Google left with no offline way to access contact info. I brought over 950+ contacts from a Palm into Google. gContactSync brought them all into T-Bird with only a half dozen issues with some of the funky contacts. I did many edits, both on Google and on T-Bird (T-Bird is 10x faster than Google) to clean up the Palm data and all changes sync'd perfectly.
To create your own collections, you must have a Mozilla Add-ons account.