I'm a big advocate of weapon lights. They go together like pancakes and syrup. Their use requires a little training to use properly though, more so than without. Because you will never need light in a more stressful situation, they have to WORK, and Surefire lights do that. I've never had one fail that didn't have a dead battery or was neglected for a long time.
I can't recall the model number, it looks like the 6P, and we were issued them in '02. They are weapon lights, they are a little different than the handheld ones in that they have the lamps shock isolated. At least the incandescent ones do.
As far as the light they produce, well, most are just a bulb with a certain rating using a "hot" CR123 battery (the Surefire batteries have more amps than average ones). A handheld is as bright as a weapon light, and a cheap one is as bright as an expensive one. Usually.
Now Surefire sent us some of the pistol grip weapon lights in the army. We regularly got to test out all the new gear, got to keep a lot of it too, provided it wasn't issued. I still have one of those $600 lights (M500?) that has the throw lever rail mount with the pistol grip/light combo. It does not have a laser, but it does have navigation lights. I can say it is VERY bright and quite tough, and it will eat up three batteries in minutes. You HAVE to put new batteries in before a mission, then use them in handhelds afterwards or for training. Is it worth $600? Absolutely not. The only reason I have it is it was free. Really only good for door kicking missions, it gets in the way for normal use, which is why the throw lever was nice... These lights are very mission specific, hence the price --if you need blinding light instantly on entry, this is it. Good for nothing else really.
I also have the Aviator something or other. It is LED, has two brightness settings, and it is WAY better than the incandescent ones I have. Too thin to mount though in a regular mount. The LED ones also don't run batteries down near as badly, conversely, they last forever.
I have a small one battery light, great for the pocket, wish it was LED though so it would last longer. Never leave without it. For CC, a weapon light is just too bulky, but one of these in the left pocket using the Harris position works great. Luckily, I haven't had to draw the weapon, but I draw the light regularly!
The X200 I have is really the best all around small weapon light. LED, bright, and tough, it also has great focus (no bright ring and dim spots like some lights, just a bright soft bluish circle with evenly distributed light). They make 'em with lasers, and these are priced just a little higher than the competition. The ad when they came out was them hammering a nail with one while it was on, don't think I'll try that with the Glock light. If you drop the coin for a pistol mounted light, this is THE one. Works well I would imagine on a rifle or shotgun too, and I think they have pressure switches. Which is what Surefire really shines on --they have a lot of accessories and something to fit everybody. They really have no peer as far as I'm concerned.