Rated 5 out of 5 stars
I've been using this addon since I don't know when. Specially the page rendition settings and connection settings. It is really the best settings plugin.
Specially it's good for tweaking things so that it uses less memory, which is an issue with laptops that are just some years old (my main laptop is from 2008, which I consider new) it has 1 GB of ram, but the browser (linux version 32 bit firefox) uses like 250-350 mb of ram without some settings in this addon, which would make firefox and the whole system slow and unusable, if I didn't change some things with this addon.
Sadly, this latest version has a bug that makes me have to have it switched off when i don't use it, because when you press some keys like ctrl+c ctrl+v and many others, even the alt gr key triggers the configuration mania window, I hope it gets fixed fast because this always the first addon i get when I have installed firefox on a new system.