I've shot with tritium night sights before, and they are completely ineffective, that is, offering no improvement in sight acquisition or visibility, in daylight, or at dawn/dusk unless it is quite dark. Fiber-optics do require ambient light to function, but they function to some extent whenever there is light available, while night sights really work only when no light is available. I don't know the brand, but there is a sight that is a fiber-optic illuminated by tritium, and that should be the best of both worlds, as it should be visible all the time regardless of ambient light.