One thing I noticed when experimenting with my new L4 is that I myself was more blinded by the white "wall"-like quality of reflected light when shining it in the confined space of a medium sized room than I was by the more focused light from my Millenium M2. I thought to myself, maybe this isn't such a good thing if I'm faced with an intruder situation in a confined space. The last thing I want is to blind myself. Personally, I wouldn't use the L4 inside in darkness for this reason. YMMV of course, but it was not an insignificant issue in my view. By the same token, outside the L4 is marvelous. This weekend in Big Bear Lake (SoCal mountains), I was lighting up much of the length of 100 foot tall Ponderosa pine trees while standing about 50 feet from their base.