It's an OK addon.
I can see it's not blocking as many "hidden spies" as other alternatives, but i do trust these guys more than companies like Ghostly and that's why i'm using Privacy Badger on all my browsers.

Detects and blocks trackers just as described. The issues are in the control page. The list for managing tracked URLs is unnavigable. It's so small that it takes ages to load them all in once you've accrued a lot (which you will because it's the internet). Then once you start editing them the list refreshes. Every time. This needs a serious overhaul, just for basic use.
I won't rate it any lower because the functionality is definitely good, but I can't go higher because of the UI.

Fantastic. Not only does it protect my privacy and see what sites are particularly shady, it can sometimes block ads without a site's annoying pop-ups.

Very Useful!