I have a pair of the Vision X Euro pattern lights on my F800GS. I have them mounted on the engine bars below the radiator so they make a noticable visual cue and are not simply blended in with the headlight to maximize the conspicuity benifits. I wanted them mainly for conspicuity since I don't very often ride in the dark, but I can assure the doubters that they do provide very usefull lighting in the dark. I know this from testing in a 1 km long tunnel on an old rail bed trail I rode out in BC last summer. The tunnel was on a curve, so in the middle it was totally black. I tried shutting off the lights and the difference in visibility was noticable. The trail surface in the tunnel was uneven, wet and was covered with the large stones used for the original railway bed. With just the headlight, it was difficult to read the surface and control the bike. With the LEDs on adding in the increased light, it was much better and I could see farther ahead as well.
exactly what I am looking in the LEDs as well On the P2D rally we end up on some challenging dual track trails at dusk and into the early evening, with a single bright headlight you don't get the spread to light up the terrain to satisfy your peripheral vision.