Reviews for Google Contacts by Urishk
Rated 1 out of 5 stars
Run windows' task manager, Install this add-on, restart Thunderbird and watch its memory usage climbing up and up (I stopped it at ~500MB... usually my nominal Thunderbird + many adds-on memory consumption is about 130MB).
Rated 2 out of 5 stars
Google existing contacts, and contacts I add using my Android phone, are synced OK
When add a contact to Thunderbird address book, it doesn't.
And... sometime it get erased !
To create your own collections, you must have a Mozilla Add-ons account.