for incandescents a higher voltage means the bulb will be brigther then a lower voltage one and even better if overdriven. But then there's mah rating or usually around 500-800 i know this is the battery consumption usually but what would be the difference in light characteristics in a 4.8v 500mah bulb and a 4.8v 800mah bulb? ahhhhhhhhhhh! it seems to get much hotter too which risks melting my plastic reflector.