I saw this on Radio Free Blogistan (Christian Crumlish) – at least on his RSS feed (the site seems to be down , at least the home page):

The motivation for moving RFB from Radio to MT is more complex. The primary impetus is Trackback. I use the Blogistan site primarily to discuss the weblog phenomenon, and most of the thought leaders in that space use TB to coordinate their conversations. TB has already been demoed for Manila and is coming to Radio as soon as Userland’s priorities allow, but I’m impatient, especially as the not-Echo discussion rages and I feel less than a full participant in the conversation.

I also find myself in the same camp on this matter:

I will also continue to use Radio, mainly because I like the news aggregator and I use it to automatically assemble all my other blog posts into one place (currently the x-syndicate category here).