Being brighter isn't the only factor to consider with headlights. The color is very important too. That pretty blue that everyone loves is inferior to a more yellow light. Our eyes don't see well with it, sure the light looks fantastically bright, but there isn't good contrast. Why do you think fog lights are often amber? I have a car with OEM HID's, and it's fog lights are a standard hallogen (that's not because the manufacturer cheaped out on it). I have another car with standard headlights to compare it too, and the HID's are hands down brighter, but it is MUCH easier to pick up a deer standing in the ditch with the dimmer halogens.