OPI have an amazing colour selection, no one could deny that. Their celebrity collections are also very pretty.
Their nailpolish tends to be very sleek and shiny on my nails but they just don't seem to be chip free for two days! They are constantly chipping off and looking terrible! I love their colours though so will keep purchasing .
OPI is often considered the golden standard when it comes to nail polish- with a price tag to match. And while this is true for most colors- it is not across the board. Some colors are very subpar in terms of quality and end finish.
The best a person can do is to read individual reviews first for the color they are interested in.
However, I agree that OPI does not stain and they come up with some really cool colors. Look out for the 3 for 2 sales that occur often to help with costs.
Tips: Go to opi.com and try the "Try-It-On Studio" (sidebar on the right)- it is awesome to try and figure out colors for your nail length and skin tone.