It looks promising. When you try to visit a page on MDL, you never get to see the page; MBBE blocks it instantly. And it doesn't seem limited to known malicious sites; when I try to visit a (probably) disposable site with no rating in WoT, MBBE again springs into action. It may be subject to some false positives here and there, but I rather prefer that over something like TrafficLight, which almost always remains green and silent.
Thanks for the heads-up about WoT. I was aware that they had been less than forward about their information gathering practices, and remember when Mozilla pulled it from the extensions gallery.