Great if you like control. I like knowing what is blocked and what isn't rather than just having an all-or-nothing approach like Adblock takes. If a site demands certain third-party content to work, I can enable it piecemeal. Works pretty well as an adblocker, too, except it's annoying that it doesn't block during initial loading of a webpage when restarting Firefox, so an ad-heavy site like Washington Post starts sucking up lots of CPU cycles with their tons of animated ads. I've learned to immediately reload the page when starting up Firefox so the ads get blocked.

Privacy Badger is probably one of the best extensions or add ons on Firefox