This light is pretty bright. I used it to blind a few guys while playing a night game and it worked flawlessly on my scar. It was a little tricky getting the pressure switch fitted in correctly because even though it sat right on the batteries, it wouldn't light unless it was firmly and completely pushed in all the way. That might have just been my particular model though. All in all, functionality is the best I've ever seen. This is a much better buy than most other lights.
1. Pressure switch comes with it.
2. Very bright.
3. If you don't want to use the pressure switch, it is easy to use in your hand or just mounted by itself on your gun by screwing in the end cap completely.
Only con I can think of is battery replacement will be expensive.