Been using one for a couple of months now, also with the RMT dual switch, prior to trying this I was pretty much a die-hard Surefire fan, still am, but figured I'd try something new, and it's worked very well on a weapon that is not treated very nicely.

It is incandescent, don't know much about any LED conversions available for it, but of the top of my head, I don't believe there are any.

The IR flip cap is more or less worthless, IMHO, at least the one that came on mine does not quite fit properly with the light mounted on the 3 o'clock rail, and when it will stay on, it doesn't like to stay closed. Not a big deal to me because I really don't use the IR filters much anyways, but it may matter to some. Have not tried the bikini caps, but I suspect that if you wanted an IR filter, those would be a better solution, as long as the strap didn't break.

I like the big positive button to push (I have the push button and tape switch backplate), but I don't like the fact that it does not have a click on setting, you have to twist a knob to get the light to stay constant on. Again, not that I expect to spend much time with the light clicked on, but I'm used to the Surefire XM07 tailcap that can be used click on.

Mine uses the slidelock mount, the mount seems very secure and pretty low profile IMHO, and the low profile of the light compared to Surefires is probably one of the biggest attractions of this light. Again, I'm a big fan of the Surefire, primarily the M951XM07 model with the thumbscrew mount, and my observations have been that the majority of people (including in the past, myself) is that they tend to tighten the screws finger tight only, and they begin to unscrew themselves, and need to be re-tightened after firing or sustained vibrations (like riding in a HMMWV turret). Also, on my primary use Surefire M951, the screws that originally attached the mounting clamp to the light to hold the dovetail have gone AWOL, so if the mount loosens or the rifle takes a decent knock on the light, the light will pop off. This was part of the reason I decided to try a new light system, not that I doubt that Surefire would take care of me if I were to ask them to repair it, I'm almost certain they would, but that particular light has been through a lot with me and it gives it character, and I am satisfied giving it a rest, it has earned its keep, it was time to try a new light, though I do have other Surefires lined up ready to take its place as well.

So far the VBL III has been through a decent amount of use, though it is still fairly new. It's seen over 2,000 rounds over the last two months, including a CAT-C course if anyone's familiar with that program, not too terribly much, however it has been mounted, carried, and used and abused daily through a pre-mobilization training cycle which included rides and training exercises in up-armored HMMWVs, battle drills, ect. Nothing too terribly intense, but I would say it's been through some honest daily USGI abuse, including direct impacts when the rifle has fallen on its side, but it's still perfectly fine, not that I particularly expected otherwise.

What I would change:

I like that it has some things in common with the AN/PEQ-2A and AN/PEQ-15 series of aiming lasers commonly seen on military weapons, and I think that the dual switch is an excellent item, however, I would like to see the activation be almost identical to the aiming lights, i.e. the single tap for momentary (I would not make it a 15 second delay like the IR versions, however) and a double tap for constant on, this would make the commonality even more effective, as muscle memory could transfer between the two flawlessly.

One of the big reasons the .mil stays with incandescent lights is to use IR filters, I don't particularly use them much, and I rarely see them used in practice, call it poor training, unfamiliarity, whatever, most guys, if they use an IR illuminator just use the one that is built into the device. IR filters work less well in actual practice, IMHO, they are usually bulky when installed, delicate, and often in the way when the cover is flipped off, even the Surefire ones that reflex back over the light's body, and get caught on things, and tend to generally make themselves a nuisance. The vast majority of people I've encountered, from service support Reservist to bona-fide operator eventually takes seems to take them off, to be honest, the people I see using them the most are the types that put the "office" in "officer." The Insight bikini style IR filter looks like it may solve the bulkiness issue, however, my experience with Insight's bikini straps on their aiming lasers tends to be that they are rather delicate and almost inevitably snap on one side after a couple months of honest use, resulting in a lot of flapping, hanging covers until they're replaced or removed. I don't know what the best solution for this is, especially since I know that IR filters have their uses, and that the option to use them is a big part of the reason the .mil has not made the switch to LEDs, but it doesn't take a roofer know that the ceiling's leaking.

Regarding the dual switch, love it, however, I wish that Insight had differentiated better between the two buttons. They are more or less identical, with the only real distinction being that one has a raised Insight "eye" logo which disappears under gloves. Perhaps a thick, molded in horizontal ridge on one and vertical one on the other might have been better? Differentiating between them can be resolved through good training and muscle memory, however it could have been made more intuitive.

All in all, the final verdict? I like it, it's compact, it's lightweight, it's sufficiently bright for my purposes (I'm not the "I need a freaking anti-aircraft spotlight on my rifle" type), and I think it's a good piece of kit. I would not hesitate to pick up another one if I needed to get another weaponlight, and would not hesitate to use either it or the Surefire M951. It's not perfect, but no piece of kit is, at least none that I have yet encountered, but my limited exposure to it has thus far left me confident enough in it to use it as my primary weaponlight. My complaints are small and could be construed as nit-picky. I will be sure to let you guys know if for some reason my opinion changes, and if so, why.