I work at an Albuquerque television station, and I had a need to modify the plugin so that general users get redirected to FeedBurner, while certain special users (a couple of our partners) get the regular WordPress feed. I figured I'd share.
Underneath the following line in fdfeedburner.php:
if (preg_match('/feedburner/i', $_SERVER['HTTP_USER_AGENT'])) return;
I added this line, replacing "partneragent" with a keyword from our partner's user-agent string:
if (preg_match('/partneragent/i', $_SERVER['HTTP_USER_AGENT'])) return;
I would love it if a similar function were added into the main code so it doesn't take some PHP changes.