I don't see the laser on the M6 as being terribly useful, either on a dedicated house gun or on a "street" carry gun. Definitely get the white-light M3, or a Sure-Fire if you want a mil-spec rugged unit, but don't waste extra $$ on the laser.
- If you turn on the light and the laser at the same time, the light MAY be so bright that it "washes out" the laser dot. Anyway, if you turn on the light, you can see the silhouette of your regular iron sights and aim with them just as well as if you were at a well-lit range(maybe even better, 'cuz you'll see them as a stark, sharp-edged silhouette, without any overhead glare).
- If you use the laser only, without the white light, you've got the aiming capability but no target-identification; the laser AIN'T bright enough to let you ID friend vs. foe reliably. If you're on a "search-and-destroy" house-clearing mission, BOTH the light AND the laser are equally as likely to give your position away UNLESS you first LEARN and then PRACTICE REGULARLY proper flashlight-assisted low-light house-clearing techniques.
- The laser will not "blind" an assailant UNLESS you shine the dot DIRECTLY into his eye(which first requires you to FIND his eyes, in the dark) - the white light WILL "blind" him even if you beam his chest, or the wall just next to his head, and you can then easily move the "sweet spot" of the beam to his eyes, 'cuz the beam has just shown you his whole upper torso.
- If you "beam" someone with the white light attached to your gun, not only can you ID friend or foe, but once the ID is confirmed as "foe," you can fire 'im up IMMEDIATELY - 'cuz you've already got the gun pointed right at him. If your assailant is squarely in the white-light's beam, you DON'T NEED the laser to "pinpoint aim" for you - if you really need to make a precise, "hostage rescue" shot, just use the nice silhouette of your iron sights that you'll see with the white light anyway.
- Yeah, the laser dot is "intimidating," but how much LESS intimidating is that blinding, retina-searing, 60 to 120 lumen white light, anyway?
The way I see it, adding the laser to the white light is just "gilding the lily."