I just finished migrating all my Radio Userland blog posts to TypePad. Nontrivial. One post had an HTML error in it that caused an import error. Many entries needed manual creation of categories. Multiple categories did not work (each turned into one long semicolon filled category). All in all it took 4-6 hours of import file massaging and category cleanup. I haven't even looked at most of the entries to see if they formatted correctly.
But at least I'm basically migrated.