A 35 watt HID lamp produces up to 3 times=300% of the lumens at the light source when compared to a conventional standard 55 watt Halogen lamp. Now that is impressive!
Normal Halogen bulb: Xenon / HID conversion kit:


Whiter Light and Greater Driver Comfort
Good visibility contributes to driver confidence which promotes relaxed, safer driving. Drivers can benefit from fitting HID Conversion Kits in their vehicles, since the white light stimulates driver concentration and makes night time driving less tiring. In addition, the HID system also delivers a marked contribution to road safety in the event of limited visibility due to weather (rain, snowfall) conditions. This is a must for safer driving.
Why was Xenon Light developed
At least 60% of all traffic accidents take place in poorly lit conditions. And the older the driver, the more light required for seeing better during night driving. Brighter lighting by xenon light means most importantly, better road safety and less strain on the eyes.
Greater Visibility and Road Safety
While driving at night, there is nothing more important than being able to see where one is going. HID lights help in overcoming severe driving conditions by providing between two to three times more light than halogen lamps. This higher light output is put to very good use, improving both light intensity and light distribution on the road, thereby widening the field of vision for earlier recognition of people and objects. An additional benefit is that the brilliant white light is reflected much better by road markings and signs which makes for more confident driving in bad weather conditions and at night. The difference you can se below.

Lower Power Consumption
A 55 watt Halogen lamp draws a constant 10 Amps, while an HID lamp in steady state draws in 3-4 Amps (50-60% less power). As a result of lower power consumption, less heat is dissipated by the HID lighting systems and more power from the engine. Additionally, you will be doing your part for the environment: less power consumption means less waste.
And if that is not enough reason to buy xenon powered lights or HID Kits, see what everyone else recommends. Xenon is a new technology in automotive lighting.