Rated 3 out of 5 stars

le Gavrahil ar Feabh. 8, 2009 · buan-nasc

Very good Add-On. Does what it advertises, but has a few faults nonetheless.
Sometimes you have to manually correct some items, but much more importantly I agree with John Pang: as soon as you're done with the duplicates turn it off, or you'll have no joy with your Thunderbird GUI.