I'm playing with a Luxeon K2 LED that I finally was able to glom as a nobody.
It is impressive. It produces 130 lumens. Most tactical rail lights produce 90 lumens or less, using xenon bulbs that last for maybe 10 hours and fail catastrophically at end of life by burning out upon turnon -- which is exactly when they're needed and not an opportune time to be screwing around changing bulbs. "Please hold, Mr Tango, I need to replace my flashlight bulb". Yoo betcha boika, I'll grab a smoke, yust holler ven yoore ready to resume da dance...
An LED is essentally immune to recoil while a hot filament is fragile though the tac-light guys do seem to have solved that issue. Beyond that, LED's do not fail catastrophically, just dim to 70% after 50K hours of service or so.
I don't know if there is a measure for dazzle power, but brightness is clearly a factor and I think color is also. The K2 is bright white,6500K color temp or so, about that of sunlight while the hottest xenon bulb is maybe 3200K with fresh batteries. I dare not look at this sucker head on, but even looking at it bareassed and sideways (10% max off angle intensity) has me seeing spots for several minutes afterwards, and a collimator or reflector significantly intensifies on-axis intensity. I think it would not only be dazzling but downright painful for young night-adapted eyes. I've always thought of railmount tac lights as an excellent target, but I think this sucker is so bright it would cause dazzle, blink or involuntary look-away, any of which work.
SWAT and spec ops guys tend not to be innovators for good reason: trust what has proven to work in shit sits because a firefight is not a good venue for experiments. DOD does research because they have the budget for field trials, though the results are often seriously contaminated by political matters, e.g. the Beretta M9 sidearm. I didn't like the M1911A1 as my assigned sidarm at all, but I'd sure as hell choose that over the freakin' M9 any day.
I definitely understand the respect for proven performance among those who need shit to work, but I thought I'd mention the new LED technology anyway.
These LED's cost about 5 bux in small qty. They do need drive elex that would be very cheap and tiny if produced in any volume.