I have the BDCW kit, the light is really bright, but I don't have anything to compare to except for the high beam.
You have to use the SR lights; I made the mistake of buying the E series and there's not enough clearance for the suspension. Even with the SR kit you can't raise the fenders. I also wasted some money on the Skene IQ-175, which isn't compatible with the SR series.
Wiring is simple, but if you want to do a clean job you have to strip off all the molding and remove the headlight and fuel tank.