I heard HD isn't doing the dual bulb in HID anymore. Too expensive maybe? Anyway I did the HID swap for mine and would bet dollar to dollar its more cost effective and brighter then the LEDs.
Another thing not mentioned a led is a lifetime bulb, so although it is initially more cost, you may never have to buy another bulb again.
I've currently got Sylvania Silver Stars (or whatever the ones in the reddish orange package are called) in my bike. If they only last a year and at twenty-five bucks a pop, it'd take about twenty years to balance out with the LED, cost-wise.