I recently purchased an LED H4 bulb for my Vectrix electric motorcycle.
I believe it's the "other" bulb shown in Daox's first photo. It's like what he is using only it has a little pig-tail to an electronics box, and then to the regular three-prong headlight connector.
Overall, I like the color temperature. The cycle already has an LED front marker light. Originally, the halogen bulb looked weird to me, because it was the only NON-LED light on the cycle. With the LED headlamp, it matches closely, and looks much nicer.
It's always tough to get really accurate photos of lighting, but I thought these are fairly representative. I took these photos at dusk.
Here's the cycle with the low beam.
Here's the high-beam.
The brightness and color are both very good. However, my first true night ride (just around the neighborhood, for testing) showed that the bulb alignment was not good. The low-beam is very bright, but it is as though it is just aimed too low.
The high-beam really shows distant reflective street signs very well.
I haven't had a chance yet to simply try adjusting the aim of the headlight.
As for temperature. I parked the cycle, but left it on, so that the LED bulb could get warm. I checked it after about 30 minutes. The heatsink fins on the bulb felt warm. Too warm for me to want to touch for too long. My IR laser thermometer only said it was a little above 100 degrees F, but I don't think it was getting a proper reading, because it's shiny metal, and it was a difficult angle.
The small black "electronics box" was barely warm to the touch at all.
The only other thing I would really mention about this is that the installation information that came with it was pretty minimal. It was NOT OBVIOUS at all that there was a removable locking ring on this bulb. It looks just like a permanent part of the bulb, and without seeing some photos of somebody else installing this on their cycle, I would have missed it completely. Once you known about the ring, it wasn't all that hard to locate, but it still doesn't jump out at you!