Рейтинг 1 из 5 звёзд

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).

Рейтинг 2 из 5 звёзд

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 !