Rated 2 out of 5 stars
Two stars for good functionality - this extension offers loads of options to change user agent, referrer, as well as IP proxy. I've just spent ages removing all traces of bundled malware/adware from my computer, along with the extension. This problem *may* not have originated with Proxy Tool ... but I think it did. Apply with caution, if at all.
In case you don't know this, EVERY single addon that goes on Mozilla.org is completely checked, every aspect of the code is inspected by Mozilla reviewers. It would be impossible for an addon developer to put a virus in an addon unless it isn't officially released on Mozilla.org
Further more there would be no reason for us to spend countless hours on a free addon just to couse people problems. We do this because we want people to like our products and website, not hate us.