In my first Birchbox order, I got this color-changing polish, Poppy, by Ruby Wing.
I like the color in it's indoor, hot pink state the most. Even though it was goopy and applied streaky, with a lumpy finish, it dried very fast and only needed two coats.
The following pictures are of this polish in progression from inside, to full-sun:
According to the sticker on the bottle, it is supposed to go purple, but only becomes a deep, mauvey red-purple sort of color. Nothing at all like the sticker shows (for either color)!
I wore China Glaze Techno over my ring finger to see if a topcoat would stop the polish from changing colors like it does with some of Claire's mood polishes, but luckily it wasn't affected by the clear/glitter on top!
I did test it out, though, and hot/cold water does not work on this one. Nor does indirect sunlight or cloud-cover. It has to be full-on, direct sunlight to change.
I'm still kind of on the fence about this one. I don't love it, but I don't hate it. I just haven't decided yet.