Firstly, I think calling this polish Rainbow is a complete misnomer. Rainbow to me conjures up a mental image of a whole spectrum of clear, vibrant, summery colours, something girly, feminine and maybe a bit sheer. What this colour actually is, is a murky, edgy, rock 'n' roll and rather androgynous drama queen. It is most certainly not a rainbow. I LOVE it.Rainbow is a multichrome that is, the colour changes or "flips" according to the angle of the light. I am a big fan of this effect. When I first applied Rainbow indoors in muted light, it looked like a murky, burnished plum with some red sparkle. The base colour is a thin, dirty teal which for me does not show up in any lighting conditions, as it vanishes with each new layer you apply. I was mildly disappointed the polish was nice enough, but pretty subtle and indoors I could not see any colour change. However when I went out into daylight I got the full effect.In sunshine the plum is no longer muted and really comes to life, the red sparkles making it almost garnet. And at certain angles, the true surprise appears an extraordinary, obnoxiously in your face chartreuse. I do not see any other colours, just the flip from plum/red to green/yellow. And it is extremely dramatic.Ok, so I love the shade, despite its misleading name. Why only three lippies?The formulation is very thin and difficult to apply well. I work neatly when painting my nails but this stuff streaks and applies very unevenly as well as being almost transparent. It does build however and the more layers you apply the less you have of these problems. I needed to apply five layers the most I've ever needed with any polish before it was truly opaque and I could see what I was getting. I think that's wasteful and excessive, and who has the time for that anyway? My beloved Barry M duochromes have gorgeous colour pop, are opaque in two layers and go on like a dream, so it can be done better. It does dry quickly, at least. The thinness and problematic application made it seem like a cheap polish rather than one I'd just sprung almost £10 on.My other problem with this polish is pretty subjective this colour only shows off its brilliance in bright sunshine, but summery it is not. If I could have that amazing plum/chartreuse colour flip while propping up a dive bar, at a nightclub or during a particularly louche Christmas party I would be in heaven. But it only works in sunshine. In muted light you get nothing at all. Meh. What a tease.This is my first Orly purchase. I love the rubberised bottle top and the colour is fabulous. But I really do think the formula sucks and it is incredibly overpriced. I would hesitate to buy more Orly products as a result, especially when I can buy better quality at a third of the price.