This a excellent addon! No need to visit about:config if I want to clean my cache. Also, lately I had to press the Clean Now button multiple times in Firefox and it would only empty a few MB at a time. With Empty Cache Button this trouble is gone. Thank you :-)
I use this constantly. Be it a web dev or netadmin, Firefox aggressively caches and can make you crazy as you develop content or have a lot of DNS changes. This makes it so easy to just get things working again.