Rated 5 out of 5 stars

Great extension, but it should come with a more complete list of user-agents built in (along with all the other variables) so that by default there is a longer list of web browsers and bots and mobile devices you can have Firefox impersonate, and also having different versions of each browser (including Firefox). Everything else about this extension is perfect, the only flaw is the rather short default list of user-agents. And it works perfectly in Firefox 8.0.