Easily one of my top 3 extensions. Adds a lot of efficiency to searching. Unfolds it's real potential, if you use a lot of search engines for more specific searches. And lots of possibilities to invoke the menu and change the way it works (e.g. toolbar, sidebar, right click menu, dragging, key, ...). Very nice and competent developer, he always had an open ear for useful suggestions. Keep in mind: Mozilla is blocking several possibilities for such an extension, so there may be some quirks. Being a developer myself, I can assure you, the developer does his best to circumvent such problems.