Everyone know's and loves OPI that's a given, but I almost feel a little bit guilty about throwing every OPI colour into the same "review basket"...
On the whole I have had great results. The colours are always stunning, the glittery ones are a must have, really the selection is great! But the price for NZ is ridiculous. I have a massive nailpolish collection and if I spent $24.90 everytime I'd be broke. Prices in the US for example are way more reasonable for OPI so maybe hunt around :)) On the whole great products sure, a tad pricey, is it worth it? For your fav shades sure, a juicy red, a nice midnight blue... but I wouldn't splurge regularly.
OPI as a brand are renowned for their epic nail polish collections, and lets not forget the quality of their polishes. Every single polish I've used and owned from OPI have never failed to deliver - high, beautiful colour intensity, a nice formulation with the polish consistency being easy to work with and the manicure usually lasts a while before chipping. I really like the fact that you can get OPI in mini's as well. I just received an OPI "It's My Year" bottle today, a colour I'm completely in love with at the moment.
Tips: Always use a base coat to give the polish a nice surface to glide onto and a top coat to finish the look.