Migrating my Blogger site to CraftCMS
I migrated a Blogger site by writing a Craft plugin to parse Blogger's XML and save images, posts, and categories into the Craft setup established with the client. The challenge with Craft is that last part: you're the one deciding how things will work, the CMS doesn't come with opinions about how your blog posts will be constructed or organized.

You can use the Feed Me or Sprout Import plugins to migrate your Blogger data, but you'll still need to set up your blog in Craft and decide how to map the Blogger data to your Craft install.

Comments are another animal. It may be easiest to move them to Disqus. I've not used this comment plugin, but expect it would be solid.