While I was not using this app to block ads on YouTube, I noticed that this app was using an inordinate amount of CPU while browsing my video feed, halting any use of Firefox for up to a minute at a time, either periodically or after a few mouse or keyboard actions.

Sure it blocks ads on other sites, but there are no ads on the home page of YouTube, so it's rather inexplicable why it would tie up the CPU the way it does for rather trivial functions. This has been going on for a while, and I am not the only person in reviews that have had the same experience, yet I see no plans to fix this, so, one star, because I can't give zero.