I bought these after reading online reviews stating these were better than the Hella H4 units. I don't really know if that is true, but I'll make some observations. These appear to be high quality lamps. The lenses are molded precisely and high quality glass is used. However the glass is relatively thin, so I am worried about these lamp's susceptibility to rock chips or even thermal shock. I was honestly expecting a bit thicker glass given the price. The bucket/reflector appears to be of good quality too, it is thicker/sturdier metal than you will see on cheap H4 lamps like Autopal or IPCW, the painted finish is also good. I expect the metal parts of the lamp to hold up well. The rubber boot again looks to be high quality, with no flashing or molding lines visible like you might see on cheaper units. It does appear to have a vent or drain molded into it, so I would worry that it isn't water tight when submerged - not a problem for me, but maybe a concern for those of you who go off road.
As for installation, like every other H4 conversion I've seen, the glass in these is maybe 2-3mm smaller in diameter than the sealed beam unit it replaces, so it may not fit tightly in your headlight bucket tightly. You might have to fiddle with it gently to get it correctly seated when tightening it down.
Performance wise these provide a noticeable improvement over sealed beam units, even halogen sealed beams. You get a brighter, more precisely aimed light. The flip side of this is you WILL have to adjust the light carefully both to make sure the light isn't aimed too high and into oncoming driver's eyes, but also because there is a dark spot where I guess the beams don't quite overlap until you adjust them so they do. So it beats the pants off of sealed beams. How about other H4 conversions? I don't have other units on hand to directly compare, but from memory of what I've had in other cars, I do have one issue with these units. The usable beam spread is actually pretty narrow. About two lanes worth. That is lit up plenty bright, and projected well ahead even on low beam. But it's rather narrow. The whole beam itself is actually extremely wide, so you don't have any trouble seeing curbs and such, but outside of the central two-lane-wide "block" the beam is pretty dim. Dimmer than other units I've used. Dim enough that you don't really notice the wider, dimmer part of the beam unless you take your eyes off the bright "block" part of the beam.
So final thoughts: A definite improvement over sealed beams, even halogen units. A good quality unit compared to cheaper H4 conversions (so you really do get what you pay for) and shouldn't rust through or corrode like cheap stuff does. As for better than Hella? Maybe, maybe not.
