The past few years have seen leaps and bounds in H4 replacement LED technology.
It's perfectly possible to marry a decent LED with a standard H4 headlamp unit and not dazzle other drivers, as well as light up the road ahead two, three or four times better then with a wheezy old filament bulb.
The trick is to get a good match - the LED MUST be one with small elements that are closely placed to the original filament positions of the tungsten halogen bulb. The next step is to be prepared to experiment a bit, and that's where Vetter fairings are useful, because they use a standard 7" headlamp.
On my Vetter, I had a choice of several, but I ended up using a Koito headlamp from a Mitsubishi Pajero or Shogun, and it was a really good match to a Nite-Eye LED H4 bulb. As well as the initial match being good, there is also scope for fine tuning the bulb in its carrier sleeve, which angles the beam cutoff to be in the right place.
I've since used the same type of H4 LEDs (with the small elements) in Hella lamp units and the results are excellent. My Vetter has been replaced with another UK-made copy of a Vetter, that uses a Cibie rectangular headlamp and it really suits the LED bulb.
There's a lot of erroneous information based on bad experiences caused by bad design.
The first LED headlamp I bought was rubbish, and so was the second. I wasn't impressed with them at all.
It was only about three or four years ago that they started to come right - but surprisingly many of the LED sellers on ebay and other places are still selling the old crappy designs - you can tell them immediately by how large the chip/COB/element size is.
