One more comparison. I always find it interesting to see the strength of different white pencils on black substrate, so here's a visual comparison for you from the brands I've been testing here. This is useful if you ever plan to color on black or darker cardstock, or if you like adding pencil highlights over marker or other precolored images. I think the scan captures the coverage and strength of each pencil brand well. There is certainly a marked difference between brands.
Here's a close-up of a sample I colored with a Prismacolor pencil - this is so backwards from the way I normally color - it's a very interesting challenge! Usually we color in shading on white surfaces and allow the white to show through as the highlight. On this piece, I had to color in the highlights and leave the shaded areas partially colored or untouched. I'll share the full card and more details another day.