Feb 24th, 2013
This is by far the coolest and easiest way to do complex migrations. Once you learn this, you will be able to migrate just about anything into Drupal including old Drupal sites where using the core updater doesn't work right because of whatever complexity the old site had.
Soon, I'll be writing up an article on using this great module... For now, here's an article that I found which is a great read for anyone who may need to use this module: http://www.verbosity.ca/working-drupals-migrate-module