Erik Speckman linked to my comparison and had these comments to add:
I’d add that updating Live Journal from any web browser is much more natural than doing the same thing with Radio. With live journal, one web browser is the same as any other because the blog management application is a traditional web application. With Radio, updating from something other than your main desktop takes some extra effort. You have to change security settings, open your firewall, keep your desktop on all the time, etc.
I have a news & ideas blog on live journal but I have always felt a bit uncomfortable with it because, at least from my point of view, LiveJournal’s culture seems much more about naval gazing and the intimate yet mundane details of people’s lives.
Oh, one other difference, Radio is better about providing statistics about who is linking to you than LiveJournal.
I tend to agree that LiveJournal’s community seems to be more of the diary type (viz. Diaryland vs. Pitas in the old days), although this is a matter of culture and branding and not so much the technology