I don't and never have owned a Surefire light, though it seems to me that they are the standard against which other lights are measured and to which other manufacturers compare themselves. Looking at their product lineup, they have obviously found their market in the LE/Mil arena, leaving the larger consumer market to other less expensive brands. Their engineering, materials, workmanship and feature list are superb, you do get what you pay for. The down side is that this means many of us can't afford them. Surefire revolutionized the flashlight world when the Maglite was king. Now they are on top but Mag is still shipping truckloads of the same lights they had out when I was a kid. LEDs revolutionized the world again but that was a wagon that everyone could jump on, and did. Ultimately the only bad thing I can say about Surefire is that they're out of my price range. Which is more of a whine than an actual criticism. Streamlight has had some great ideas and fair pricing but as far as I know has never used anything but plastic lenses, which get scratched up over time. I've completely given up on them. In answer to the original question: Brand loyalty, nationalism, bragging rights, and outright quality.