All nail polish lovers need some OPI in their collection. I avoided it for the longest time because of the price, thinking all polishes are fundamentally the same...it's not the first time in my life that I've been wrong.
Firstly, these polishes tend to be much larger than other bottles, so you'e getting more product. Secondly, the brush is a good size for application, not too big or too small. Thirdly, The colour range is out of this world, whatever colour you're after, they'll have it! And lastly, it lasts on your nails brilliantly with a good base and top coat, normally about 5 days without chipping.
I've found that the formulas can differ, which I suppose is to be expected from a line that provides soo much range. For instance, the pastel colours tend to chip easier than the standard, generally darker coloured, formulas. As a result, the opacity of the formulas can differ also, but generally they're pretty awesome.
Love love love this white nail polish it truly is one of the best whites, it comes out pure white sometimes my mum thinks it twink :). It's super long lasting and lasts a few weeks of wear. The price is pricey but totally worth your bucks.
Tips: Apply 3 layers for maximum whiteness and also apply a top coat to keep it from chipping.