In the end, I decided to go with EduBlogs, largely because it let me moderate comments from students, but I have to admit, I wasn't thrilled with it. It seemed clumsy, difficult to design with and... well, ...
You know what? That really doesn't matter, because EduBlogs has redeemed itself with a semi-new feature - I can edit blog comments before posting them.
No, seriously - this is a huge deal for me.
In order to protect student privacy, my policy is that when students post their blogs as comments, they identify themselves with only their first name and last initial. Invariably, some students forget and use their whole name. Last year, when that happened, I'd have to copy their comment, paste it into a comment myself, remove the last name, and then repost it with a short message explaining why their assignment was posted under my name.
I realize that there are ethical considerations involved in changing someone's comments before publishing them, but in my particular case, I think those are outweighed by my ability to publish them quickly, safely and with instant-ish feedback.
Congratulations and thank you to EduBlogs.
(And to Ted Knight and Rodney Dangerfield, wherever you are. You are both greatly missed.)