Im not a big fan of the yellow light, I prefer cool white. All my games range from 1980 to 1983 and I think LED adds a modern touch to them which makes them look like a more modern machine. I think regular bulbs are more suited for EM's because they have that antique look to them and should stay that way. One thing that should never be done with LED is to over do them with different colors. I dont want to look at a rainbow when playing a pin.
The beauty of the LED vs bulb argument is they can be changed easily. Its a great way to personalize the machine to the individuals taste.