Some of my thoughts on the Modlite pistol light...
What it is:
The Modlight is maybe 3/16" longer than the X300U and fits in the Safariland SLS and ALS as well as US Duty Gear holsters I've used with Glocks, Staccatos, and M&Ps. The body is thinner except where the switches sit so other than the length of the head it looks a bit more slim and compact. The switches feel good. They move without too much effort (some Surefire's can be tough) and from the few I've seen they are very consistent. They click positively into position and are easy to manipulate with the support thumb. In fact, with minimal effort they can be controlled almost as easily (though not quite) as the momentary function of the Surefire. I'm not a huge fan of the momentary function so I am ok with it not being there. I bet it could be controlled even easier with the supplied ARC switches but I haven't tried them. In fact... I'm not sure where I put the box. At this point the only thing in my life that's organized is my optic mounting kit. With everything else all bets are off.
I do prefer the ability to use a pressure switch, and the switching system is housed in the rear portion of the unit attached to the body with four small screws so I'm hopefull that a pressure switch could be incorporated into future designs. For a "toggle-only" system it works well and like the Surefire it's completely ambidextrous which is nice. I like Streamlight lights and have a bunch, but I don't like the teeter-totter switch that works different depending on whether you're right or left handed.
I really like that this light uses a single 18350 battery. They are easy enough to find (from Modlite and elsewhere) so you can have a bunch on hand. In addition, I picked up a solar charger from Cloud Defensive a while ago and can re-charge the battery a couple times at least with it while also letting the charger re-charge during the day. This could keep a light going a while with no power and no access to retail. Not trying to be a crazy prepper, but I like that option. The use of a single battery also allows the body to be thinner than the side-by-side battery lights as I mentioned above. I was told battery life is something like 35 minutes, and I'm assuming that's regulated output.
The light output is typical Modlight impressive. I'm a bit of a low-light/flashlight nerd so I have some decent lights that are well over 1000 lumens and a couple that are much more. I know people will argue that this is "too bright" for a pistol light. I might agree when we reach the point, as Pat Rogers would say - that when activated the person "changes shape or catches fire" but until that time, I want lots of light. "But... It'll DESTROY your night vision!"... Yes. Yes it will. So will the 300 and 500 lumen WMLs and I don't care because that's why I turned on a light. Add to that that it really doesn't destroy your night vision if used correctly. Sorry... Rant off. It is a tight hotspot with decent spill for indoors but I'm looking forward to see what that "coming soon" head will be like. Outdoors this thing is a beast. I've taken 100 yard pistol shots in the dark with it. That's cool. Of course, that's less than likely, but getting that much light on a threat makes this light provide a clear visual picture where other lights allow you to "see" but maybe not "ID".
So what do I think of it compared?
I won't be selling any of my Surefire or Streamlight lights. They have options (depending on the gun) for pressure switches and support primary CR123 batteries that are common and in many cases supplied by one's employer. The Modlite is certainly brighter and that's cool, but the current X300Us and TLR-1HLs are certainly not bad in that department - Making the Modlight really come into it's groove at those longer distances. If I worked an agency or assignment where I couldn't use a pressure switch (say running NVGs on a regular basis), this would be a strong contender for the #1 spot.
All that said, what the Modlite is now isn't what I'm excited about. It's just one evolution (in brightness) past current WMLs and the switching, while good, isn't some crazy breakthrough. What makes me really like this light is the fact that it is modular. As I mentioned, I'm hoping they develop additional tailcap options for pressure switches, though I'm not sure that's in the cards. What I do like is that the body is slim and short and could easily be a compact WML with a different, smaller head. Here's the body on my Staccato C2:
It could be an IR WML with a different head. It can be configured for spot, flood, CRI, and other factors that could really allow the user to tailor the light to their needs and adapt the light to future needs and technological advances. This is something that simply hasn't existed with WMLs of the past and most of us have either relegated old lights to drawers, given them away, or otherwise disposed of them because they were no longer relevant. My first WML was a Streamlight M3, followed by a Surefire X200 when it was released. I still have a couple of old Nitrolon weaponlights laying around until I decide to declutter them.