Rated 4 out of 5 stars
I have been using 0.8.38 with thunderbird 11. Periodically, the sync script pops up a box saying it stopped responding. This seems to happen after contact changes were made on the google side. After a few restarts, everything is ok again. I am syncing the addresses as xml.
I see there is a 0.8.40 version on the zindus website but am reluctant to try it since it has not been accepted by the mozilla add-on search. Also, cannot find release notes for 0.8.40
Overall though, the syncing is doing what I need so I can maintain my contacts on both ipad gmail and thunderbird.