The color is really well balanced between lavender and grey. Depending on the light it leans more one way or the other; since I like both colors I'm happy regardless. The shimmer is on the subtle side but definitely visible in normal room light. In the bottle, I thought it was silver shimmer; on the nail I think I see pops of blue and pink. This was a two-coater for me; all these swatches are without top coat.
Since purple is my favorite color and I have so very many bottles of it in my collection, I thought for sure I could find something close to My Kind of Cool Aid. So far, I haven't. Still, I thought it might be good to share what I tried for comparison purposes so if you have some of these you can see how the Cult Nails compares. Two of the ones I pulled to swatch were Rimmel Fast Play in Hit That and OPI Sheer Your Toys.
Rimmel Play Fast (I'm still miffed they discontinued these) Hit That has a somewhat similar base color but is too grey to be a match and the shimmer in it is peach/gold, not silver/blue/pink. OPI Sheer Your Toys is much, much lighter and has those weird copper flecks in it, though the other shimmer is closer to Cult Nails than the Rimmel.
I also tried one of the European polishes in my stash, P2 Color Victim in Elegant.
Again, not a match. The P2 is in the same family for sure, but the base color is lighter and the shimmer is more subtle. I'm hoping to do a bit of a stash reorganization next week so perhaps I'll turn up another polish or two to compare; right now I'm pretty sure this one is unique in my collection.