Movable Type is a fantastic blog publishing platform. I think a couple years ago, other blog systems seemed to have clear advantages over MT, but now that it's free and open source, there's a lot to be enjoyed. Six Apart just released Movable Type 4.21 that contains a host of new features and critical speed improvements. The back-end blog management tool is the best-looking I've seen. I highly recommend it.

Another great reason to use Movable Type is the free iPhone web app that is available. It's a plugin you can add to your blog called iMT. It's super easy to implement. You simply upload two folders to two spots in your MT installation directory, and you're done. Your blog admin will be formatted beautifully for Mobile Safari on the iPhone. Nothing else is required. I've included a few screenshots so you can get a good feel for the elegance of the web app:

While I still think it would be cool if a thick app came out for the iPhone, this implementation is certainly worth using in the meantime. Good work, Six Apart. I can't see myself ever using another blog system as long as they keep up with the improvements.