Works great! Rated 4 out of 5 stars

I haven't really had any trouble with this add on! I would like to be able to turn flash off on "separate" tabs though, it messes things up.

This review is for a previous version of the add-on (0.8.5). 

Thank you for your review!
Like the description says, this addon completely disables the flash plugin.
If you only like to enable flash for some sites, then you should try the build-in firefox "function" click_to_play. It disables all plugins (also java etc) by default and allows you to temporarily or permanently enable plugins on a per-site basis. (and even single applets on a site!)