I'll tell you this. I've had my wife shine my SF into my eyes to see what it'd be like, and with a light that bright, it's hard to tell where it's coming from, let alone aim at it. That little 6P throws a beam large enough to cover the entire wall at 5 ft., with the most intense portion being 2 ft. in diameter. Assuming I'm not being robbed by Verne Troyer or Yao Ming, I'll be close enough.
My plan isn't to blind someone into submission, it's to flash the light at them to identify them, and if they are ID'd as a threat, disorient them long enough to take the shot. I really see no need to have a pointy light, my gun is a better bludgeon if things go that bad.
It is foolish to have an HD gun without some kind of white light, be it handheld or weapon mounted. The brighter the better IMO, so long as it's small enough to have handy and not be encumbering when handling the weapon.
fireman- the SF I have with an LED head has probably 5 hours of runtime on the original batteries (still going), although not all at one time. They claim 11 hours.
I know I sound like a SF salesman here, but once you try one, you never go back. I would assume any of the major brands like Streamlight would be equally good, but I haven't used their products outside of the big lanterns and 4AA helmet lights we have at the FD.