Here's my latest swatch, for Sephora by OPI's grey-purple color "On Stage".
Originally I bought this color as a substitute for the color "Call Your Mother", another grayed, muted purple shade. Since my local Sephora was out of that, I thought "On Stage" would be a good dupe. I'm a little undecided about this color. It's darker than that of "Call Your Mother", and though I thought that would be no big deal, I like it significantly less. It's just sort of dull, but not dull in a cool, avant-garde way.
I would say it's appropriate for adults, and could even be worn to work since it's not bright or too eye-catching. Consistency-wise, one coat was too thin and uneven, but two seemed just right. If you look at my nails up close however, the polish is still uneven in places. Hey, maybe you'll like it, but I'll still be on the prowl for "Call Your Mother".
Hope this helps! Feel free to comment your opinions or request what color out of my collection you'd like me to swatch next.