this is one person's reason behind his switch from Movable Type to WordPress:
http://diveintomark.org/archives/2004/05/14/freedom-0
here's a Slasdot article regarding the change with Movable Type.
here is a page that helps with the move from Movable Type to WordPress:
http://blog.carthik.net/vault/2004/05/14/movabletype-to-wordpress/