Rated 3 out of 5 stars
I am running Linux and I am using the imap folder method.
My contacts synchronise well but the lists are lost. I suspect that the problem is a combination of the way Thunderbird works and some sort of merging or tidying that this tool seems to be doing.
Load and save at the start and at closing when I log out of the pc works well.
My plan is to try another tool or Symlink to share the abook.map on a cloud folder. I may return to Address Synchroniser