I actually have the G2X Pro, which produces 200 lumens instead of 120.
-Protective twist cap to prevent accidentally turning it on.
-Really focused light beam.
-Not as small as they make it look in the picture.
-Unique non-rechargeable battery that's costly to replace.
I have the G2X as a backup to my normal headlamp. It's mostly for my night Time hiking/photography trips, when I need a bright and focused light to see my subject before I do long exposure shots. The light beam is very straight and focused, I love it.
It can also be used for self protection, as I learned when I first opened the box. I turned on the light and the first thing I did was accidentally point it at a co-worker straight in the eye. He literally stumbled back a few steps. lol.