I'd been thinking about writing a detailed comparison between the features of TypePad and Radio Userland, now that TypePad is available to the public. Two things have kept me from finishing that post: 1) the full comparison keeps ending up as long as a book, and 2) I have not actually used TypePad and do not intend to do so in the near future, which probably isn't fair to either one.
Radio Userland isn't perfect, but there's a few reasons why I'm using it now and will continue to use for the time being:
You can host a Radio Userland blog anywhere you can FTP to.
Radio Userland stores the database of posts on your local machine.
Creating and editing posts occurs locally and does not require an online connection.
Comparing the feature lists of each one can be misleading. For example, both TypePad and Radio Userland both have comments. But Radio Userland's are sub-standard (unacceptably so, in my opinion), as Radio Userland offers no ability to manage them whatsoever. You cannot edit comments, delete comments, ban posters by IP address, etc. All anyone can do is post comments, period. That is why I disabled Radio Userland's comments on my blog and use HaloScan instead.
If anyone has a question about Radio Userland's features, ask it in the comments. I'm going to stay out of the way for now and watch how well people like or don't like TypePad.