It certainly does what it's supposed to do, and does it well. I enjoy using it.
Must agree with Mr_Blue_ in that the settings menu needs work. Hence one star less.

The other missing star is because this is compatible with Firefox Mobile, but the implementation really needs work there. It blocks the popups, all right, but the problem is that you have no easy access (or access *at all*) to the settings; there are no options of any kind in about:addons and, when the popup is blocked, you get no warning (the box with trust/deny/redirect/etc.), which hurts its usefulness. Sure, part of it can be blamed on Firefox Mobile being what it is, but still...

I'll gladly change the ranting once the concerns are addressed.