sigh.
The strobe (at night) is pretty effective. However, a lot of people have wrong ideas about the effect. It does not cause the attacker to writhe in pain -- it distracts him and lessens his reaction time for a crucial few moments. As a defender, you have to know what to do after that. If you buy the Gladius for defense and think that's all you need, you're dead wrong -- maybe literally.
At daylight, the distracting effect is lessened, but nevertheless something is there. I strobe people frequently (university/college, to give you an idea
) with normal work lighting, which causes people to blink, turn away and cry "Stop that!" Would it help against a determined attacker? Maybe. I don't know. Wouldn't bet my life on it, either at day OR night.
And the Gladius has so much more to offer than just the strobe, though some of it might not be seen. High quality does not necessarily mean more modes, higher brightness or more listable features. Adjustable brightness, low low setting, thermal management, one of the best UIs are the high points I can think of the top of my head.