I installed the plugin on WP 3.5 B3 on an Nginx server and created 1 redirect to return a 301 response. Looking at that in Firebug, the URL is in fact redirected but Firebug only shows a 200 response.
By comparison, the Redirection plugin in most but not all instances shows a 301 status on the old URL and a 200 status on the new one, which seems to be the more correct behavior.
Thoughts?