I took a picture of some of the various greys, with a white balance card (your monitor might have different color calibration than what the colors are in reality). It was fun comparing each with my SO to see which matches her board...like picking the paint color for a kid's room or something.
1. Stone Grey
2. Glock Grey 4. Cobalt
3. SIG Dark Grey 5. Magpul Stealth Grey
Some notes:
*The Glock Grey had a bit of a bluish tint.
*Cobalt has a slightly rough, fine texture, with tiny sparkles.
*Magpul Stealth Grey is hard to distinguish from black. It's the most charcoal of all the greys.
We went with SIG Dark Grey because it was a true grey, and was darker than Stone Grey. Beautiful colors all around.