This plug-in redirects requests to the main or comment feeds, and only theses two, to Feedburner or a similar service. In comparision to the original Feedsmith-plug-in is has three advantages:
It redirects only the two main feeds of the blog and not all. The category, tag and author feeds are still accessible
If you need access to the original blog feed you can add the URL parameter “noredirect” (i.e. /feed/?noredirect) to your feed address and it will not forward your request.
The Plugin is more integrated into the administration interface. It adds its settings to the default “reading” settings pages and do not create an own page.