Well, after all of this time I have switched my blog from MovableType to WordPress.
The reason being that MovableType’s (paid) licenses only allow a small number of authors to participate in posting to a blog. The model they use is basically that of the “lone author” who writes a blog in first person without collaboration from others. What I have found is that the best way to keep a blog fresh, growing and fluorishing is to have several authors, each of whom posts periodically. That is prohibitively expensive using the MovableType model.
WordPress, on the other hand, is free software and open source. And thus it can be modified and improved. And the team of folks working on this software has done a marvelous job. It has everything I could want.
So it may not make a difference to you the visitor to my blog, but it makes a vast difference to me, to non-profits and NGOs and everyone who likes the “group blog” model.