Rated 5 out of 5 stars

Why would you need this when TB supports RSS feeds? Well -
1. TB does not support OPML import where the feeds are organized into folders. You will need to recreate your folder structure ... or use Forumzilla.
2. Why create your a new News account, when all you really want to do is to store feeds in your local folders?

Use along with the ThunderBrowse add-on for a smooth feed reading experience.

Drawbacks: It would be nice if Forumzilla could add feed urls to the mail.trusteddomains list automatically.