Been using another plugin that's not been updated for 2 years that could move one comment at a time, but took no account of threading which meant it was a PAIN to move threads. Took me days to move around 500 comments around a site that were made on one post.
This is easy to move entire threads, few clicks and 1 to dozens of comments can be moved. Just moved a few hundred comments from one post spread over a dozen posts in half an hour.
Works with multisite and the domain mapping plugin as well.