The reason for the 3 stars: I've been using uBlock for about 2 years now. Extremely efficient against ads. But too demanding performance-wise.

Basically sometimes my FF becomes literally unusable, it freezes up for 5-10mins. I sometimes have to restart it 3-4 times to get it to load my first page! At first I thought it was FF itself and was actually looking for an alternative browser, but then I got a hint that it could be the ads + uBlock. So I disabled it and IMMEDIATELY FF started normally as if the freezing that was happening before did never happen. I was really shocked that uBlock can have such a negative effect performance-wise. But now I am sure it is uBlock.

I am going to switch to another probably less efficient adblocker. But I cannot sacrifice that much performance even if it is for good ad blocking.