I purchased this in the shade Poppy because I really liked the sample I received in a Birchbox (that one was the shade Ride 'Em Cowgirl).
This polish's formula is very nice -- smooth and creamy and very easy to apply. It took two coats to reach opacity.
Poppy is a very bright, almost Barbie hot pink indoors... and completely changes to a beautiful deep berry purple in sunlight! (And, as a bonus, in dappled sunlight or during the transformation process, it's a cherry red color!)
I have found that over time (we're talking, like, ten days after application), the polish seems to darken a bit. I think that's probably because of changing shades several times? But shame on me for leaving my manicure untouched for that long! (It's just the color-changing is so fun!)
The one thing about this nail polish that I'm not ecstatic about is the scent. Instead of smelling like poppies, it sort of just smells like vaguely-poppy-esque nail polish smell. Like a mixture of floral and nail polish, which, honestly, isn't really better than straight-up nail polish smell. It doesn't smell worse than any other polish, though it is fairly bizarre to be able to smell it even on your dry nails. I would be just as happy with this polish without the "scented" business. It's just "eh".
All in all, I really love this nail polish! If you like having a secret different nail color up your sleeve (or, just, very close to your sleeve?), then this is the stuff!