Rated 5 out of 5 stars
I use this addon to syncronize my 6 device (3 with Android using Google contacts) and 3 with Windows 7 (work and home desktop and notebook) using Mozilla TB.
Besides I suggested this app also to my wife who has 2 Android devices with Google contacts and her notebook running TB.
No problem at all with text fields of the contacts. I had only occasional problems with some photos of the contacts which disappear or duplicate in the local (TB) database.
Please note that I also use among the other extensions (more then 20) MoreFunctionForAddressbook and I have a contact list of 410 persons on my Google account on GMail.
A last note: I have no mailing list on my GMail contact list.