Reasonably fast, suitable for privacy in many cases. I do not believe that any free browser extension keeps someone *completely* safe, so don't try to do something illegal, nasty, or which requires extreme security.

Be aware that this may cause some sites to work incorrectly. Using the method of deactivating and testing each of my extensions, this one was the culprit on one of the main sites I visit. Not a deal breaker, it can be disabled for a spell and then re-enabled when it suits your fancy.