Fan-dam-tastic! Rated 5 out of 5 stars
Fabulous, fabulous program. As others have said, it took minutes to set up, and and the context menu lets me add dangerous sites as I 'stumble' onto them (as though I'm not really looking...). I'm still trying to figure out how to make access to options and about:config difficult but not impossible, but that's mostly because I'm too lazy to go beyond simple setup. Thus I use the lockdown feature a lot, usually when I first get into the office or home from work, before my head has attached itself to the computer.
Can't recommend it strongly enough. Bravo, Mr. Anderson!