I've played with HIDs on my other bike and I don't think is worth the effort. Main downside is the reflector which makes a scattered pattern and produces more glare than useful light. It may appear brighter to other road users but I found the Osram Night Breakers produce more light on the road. There is also a lot of wiring and ballasts to hide which I couldn't justify.
My opinion is that, unless you convert the headlights to proper projectors, hight quality halogens are better than HIDs.