An important distinction for me with the L1 is that it's a tactical light FIRST that can also do utility/everyday work SECOND.
Tactical has become a marketing term meaning "painted cool colors and expensive", but at it's truest form, it means "for use while employing tactics", which is addressing the threat of adversarial human beings. The criteria for a tactical light being: a momentary switch with the ability to identify a potential threat, deliver an amount of light that can affect their vision, and navigate an environment in low/no light. The ability to not only have a momentary light source, but be able to convulsively hit the button and get to high mode (as long as the tailcap is screwed on tight enough to engage high mode) with no turning selector rings, no tapping, no clicking, no sliding, makes it the number one choice for the following criteria:
1) Tactical ability: The roughly 80-100 lumens on high is just right for searching inside or outside a structure. The throw gives you a good beam you can put in a potential adversary's face to identify them. The momentary button guarantees that you won't accidentally push it too hard and click it on. If dropped, it will shut off and not illuminate you.
2) Everyday Portability: The other side of the L1: Able to be carried in a pocket as an EDC utility "always have it on you" light, no clickie to be stuck on by other objects in the pocket (I've had the L1 blink on in a pants pocket once or twice if I move a certain way, but it cannot be stuck on), something that you can choose to clip on the outside of a pocket if you're wearing jeans or cargo pants, but can slip into the pocket with khakis or suit pants. It can be clipped on a hat, it can be turned on low for close-up utility work, it can be diffused with the cap from a water bottle.
If you can name another light with that amount of output, with the intuitive convulsive interface able to get to high mode under stress without looking at the light, the option of a lower-output setting, with the solid Surefire build quality and product support, handy enough to keep with you 24/7, I'd love to hear about it.