Meant to do this a long time ago, and wish I could do a better job - but anyway this'll give you a good idea of how this particular light works. My camera wasn't really getting the job done with the apartment any darker than it is, but you can see - the light is plenty bright with the lights ON. I'm a righty, and I have the TLR-1 mounted on the right side of gun, with Streamlight's magazine tube mount. I can easily manipulate the switch using my left index finger, without shifting the rest of my hand on the forend. I took these holding the shotgun with my right hand and the camera with my left - that's a workout!
This first shot was taken with the camera aimed at a mirror, I promise I didn't lie about which side the light is on.
This is about 20.5'.
Here is 13', keeping in mind typical home defense shooting distances.
I haven't tried out any other weapon lights besides this one, and I'm perfectly fine with that. This is an awesome torch, reasonable price, easy to install. Win, win, win. Buy one.