Alright, the upgrade to Movable Type 4 is nearly complete - at least for now.
I've utilized the new comment authentication features of MT4 to let comments come back without an excessive amount of spam. I do, of course, fear that it will come back.
At the moment, comments are unmoderated. They may become moderated in the future.
I'm also planning to allow TrackBack pings. Not that anybody has ever in my life pinged something I wrote, I'd still like to have the option - especially for when some of my new content is ready for publishing.
Overall, I like MT4. Though I have to ask myself - why did I just spend my day doing this? Alright, I've got some new options and that's great - but did I need them? Probably not. I had to re-create all my CustomFields data to make the appcasts work again, which really pissed me off and, of course, didn't get me any better off than I was before the upgrade. And MT4 appears to be quite slow - I hated rebuilding my site to test stuff, but now it's excruciating!
I did also add a "Digg button" option for my entries. I'll likely start turning that on for some of my more useful posts.
Overall, I'm not unhappy with MT4 - but I'm not loving it.