Rated 4 out of 5 stars

Sadly the addon doesn't work with saved search folders, it just prints a "no such folder" message. Creating an empty folder and copying the messages does the trick, but this is a must.
Also saving messages as HTML and/or plain text would be very nice.
I'd like to see SmartSave integrated in the TB codebase soon because mass exporting messages is one of the thins TB is really lacking. Bug 258570 "Add ability to export multiple messages to .eml format" was posted on September, 2004... but so far seems to be considered a very low priority bug.