I carry the Gladius by Nighthawk and love it. It has different functions where some of the other flashlights don't. The strobe feature is great for CQ!! The only thing that bothered me at first was, I'm used to using the big mag light at night on traffic stops so when I first got it I would go to tuck it under my arm and its little tough since its so small haha. I got used to it after a couple stops.
Here's a review that I posted up for you.
The Gladius flashlight is a pretty good flashlight overall, but after seeing several new LED Maglites, LED Streamlights, Surefire Leds, and the new Pelican 7060 Led Flashlight, I have to admit that the Gladius is not THE brightest light on the market. I will list its advantages first, and then its disadvantages.
Smaller than Maglites, most Streamlights, and smaller than the Pelican 7060; Rated at 90+ Lumens, which gives it tactical use; It is lightweight, has good ergonomics; You can use the light at full power, which will last 90 minutes, or you can dim it to the lowest beam (.8 lumens), which will allow the battery to last for several days; its dimming capabilities allow you to use the necessary light for whatever task you are engaged in (i.e. you don't need 90 lumens to read a document in the dark, so you can dim the brightness down); the Gladius has a strobe mode, capable of disorienting a non-compliant or hostile individual (although the strobe mode can cause seizures on a small percentage of the population who is sensitive to flashing light patterns); the light has a lockout feature to prevent accidental activation which will drain the expensive CR123A batteries; the light is well balanced, and you can use it either mounted on a weapon, or in your hand by using several tactical flashlight techniques; the Gladius has a smart electrically regulated package that will adjust output when the light begins to overheat; it is also electrically regulated so that its brightness does not dim as the batteries get drained; the LED bulb should never burn out; and finally the flashlight will flash every fifteen seconds to alert you when the batteries are about to die. Another nice thing is that the presentation that the Gladius comes in is really nice: It comes in a hard plastic box with two Blackhawk batteries, instructions, a lanyard, and its protected in foam padding.
If you like a solid, heavy flashlight then the Gladius is not for you. Don't get me wrong, the Gladius can take a beating, for it was made for close quarter combat. However, it's body/barrel is not made out of aluminum and it is very light. This of course is only a matter of personal preference.
If you have worked with tactical led lights such as the Pelican 7060 or the Surefire E1b "Backup" mini light, you will be somewhat disappointed at the brightness of the Gladius. The Surefire E1b is rated at 80+ lumens, whereas the Gladius is rated at 90+ lumen, and yet the Surefire is visibly brighter than the Gladius, even though it is only half of it's size. The Pelican 7060 (130 lumens) outperforms both flashlights.
The Gladius is not rechargeable. Putting rechargeable CR123A batteries into the Gladius (especially rechargeable batteries from Asia found on eBay), might damage the electrical circuits on the Gladius. This means you will be spending tons of money on CR123A's. This is why perhaps you would be better off getting a rechargeable light. The Pelican 7060 is brighter, its rechargeable, lightweight, and it ranges from $110 to $150, where as the Gladius has an outrageous range of $170-300.