This is a HUGE subject of debate.... needless to say, it is probably not something one could sum up quickly on this forum.... I'm a big nerd about optics, and even I waver a bit back and forth between which has the advantage. I will say, generally speaking, if you are using a yellow fog, which has a yellow lens, it makes yellow light due to a filter, which means the raw lumen count you are putting on the ground is going to be lower. I personally believe the yellow light is better for contrasting in reduced visibility situations and that the light has less detriment to your night vision than full spectrum light, however, like I said, it is a subject of a lot of debate, and unfortunately, despite how much I like to nerd out over optics, I do not know enough about human vision to give you an answer that is much more valid than any other opinion. If you search the lighting forum on here, I have had some pretty long discussions with some other people about this subject.