I won't go into all of the details about why I switched my blogging platform from wordpress.com to blogger.com, but the biggest reason is that Blogger will host a custom domain for free, whereas WordPress charges $10/year. Yes, $10/year is peanuts, and you're free to host your custom domain with them, but I like free.
I had existing posts, and I decided that I wanted existing links to work so that if someone went to http://paul.stadig.name/2007/10/26/the-state-of-rdf-support-in-ruby-2007/ they would not get a 404 or a redirect or a jump page with an "oops-this-site-has-moved-click-here-to-go-to-the-real-site" link. Instead I opted for existing links going to a page that includes the original content, plus a little message that says "You're viewing a 'classic' blog entry. Check out the latest entries." This can be done with the Blogger missing files host.
My next problem was that my missing files host would have to be a server somewhere that I had to pay for (hmm...not free). Instead I decided to use the Google Sites service for my Google hosted domain. I created a site and created a structure to exactly mirror my existing links. I went into my Google Apps for Your Domain control panel and added a domain mapping for my new Google Site. Then I was able to test each post by replacing "pjstadig.wordpress.com" to "paul-classic.stadig.name" in the URL in the browser bar.
I wouldn't have gone through this whole process if I had hundreds of posts. However, for the small number of posts that I had, this was an ideal solution.