Today I have a comparison for you guys, a very requested one even!! When I posted the Orly Mineral Fx Collection swatches a lot of people asked to see Stone Cold compared to OPI Swimsuit...Nailed it! I wanted to do this one so badly but couldn't find my bottle of Swimsuit..but I finally found it!! Alright so, are they dupes? Nope...they are sort of similar in sunlight. The Orly is much more of a glitter and the OPI is a shimmery foil. In sunlight the base colors look pretty close but you can still tell the finish is different. In the shade you can really see the difference between these two, both in base colors and in the finish. I really like the formula on both, both are full coverage in 2 coats! Do you need both? If you like blue, I think yes...I'm happy to own both, they are gorgeous!