People around here have already discovered that the Digilight DRB-12VHP, when they get the actual high-efficiancy version, is brighter than a surefire P91, and uses significantly less power. (around 10-12W, compared to the P91 at over 15W)...
not to mention, almost every other 9V surefire P type lamp available through other sources, is brighter and whiter than the stock P90 that comes with a Surefire. (HP G90, DRB-9VHP, Wolf Eyes D26, etc)..
Don't take it the wrong way- I'm not meaning to sound like a Surfire hater, I just think their lamps seem a bit dated based on comparisons I have read around here. I should also mention, that I have a P91 on the way from surefire (should be here tomaro) that I intend to use in my 2x17670 light, because it is still the king of output for 9V tactical lamps. (to heck with runtime, I want more lumens!)