I use highlighters almost daily, and I have grown very fond of the yellow ones. They are usually not too garish nor too dark to ruin a text. The yellow markers also allow you to fotocopy a page without rendering marked bits unreadable, unlike the blue, green and orange ones. In addition, yellow markings seldom bleed over to the other side of the paper. The other, darker colours often do, especially with thin and/or low-quality paper.
However, not all yellow markers are good. The ones at sale here in the Göteborg area (west coast of Sweden) are next to useless. I’m talking about brands like Timing, Bic Brite Liner, and Pentel Handy-Line, which seem to be the only ones sold around here. Their yellow markers are either too glossy or too light, and the markings rub of very easily. After not very long (usually within a year), the yellow markings have paled and become completely invisible. What exactly is the point with marker pens like that?
A few years ago, there was another brand of marker pens at sale here. They were called Accent and were made in the US. Their yellow marker was a bit darker than that of the other brands. Not too light, and not too dark. It was somewhere in-between glossy-light yellow and too-dark orange. It was almost ochre. Markings I made five years ago are still visible and show no sign of either rubbing off or paling. I want those highlighters back in our local stores!