Superb! Rated 5 out of 5 stars
There is so much posted on YouTube that is immature, ignorant, and unintelligent. This weeds them out. It blocks comments and gives the reason why. You have the option of showing the individual comment if you like.
A previous reviewer, Firefox Foreva on March 11, said you can't turn off all comments with this addon, but that is not true as it is one of the options you can set.