Weapon Light

[BlackKnight]

It all depends what you're going to use it for and how much.
I made my choice based on when I was the SWAT team. We did a lot of shooting including lowlight training. I saw a lot of light crap out. Couldn't handle the recoil as well as the bezel got really gummed up with carbon.
At the time Surefire and Streamlight were two top contenders, I chose Surefire because I found it brighter, slightly smaller, lighter, and brighter. It was also easier to put on and take off the weapon.