Rainbow is a sheer pearlescent white with a lilacy purple duochrome. This was opaque in five coats... I know right? But I quite liked it at five coats. I prefer this being sheerer though; if my nails were in better condition I'd wear just two-three coats of this. It makes a nice layering shade, one coat over other polishes you have. Doesn't really matter what colour I don't think.
I have OPI Fly on my pinkies to *attempt* to show you what it looks like layered.