Rated 5 out of 5 stars

Works very well in Firefox 17 and lower, but is completely broken in Firefox 18; not any automated switching method works any longer, so the last entry is always selected. This could be because proxy handling was changed in Firefox 18.
"Improved responsiveness for users on proxies (769764)" in http://www.mozilla.org/en-US/firefox/18.0beta/releasenotes/

This review is for a previous version of the add-on (2012.1-signed). 

We tested with:

- Windows 7
- Firefox 18beta1 (default theme)
- MM3-ProxySwitch 2012

It works fine.