Urban Decay Revolution lipsticks retail for $22 and come in 22 shades (3 are exclusive to the Urban Decay website). The lipsticks are packaged in beautiful pewter colored metal tubes with a royal purple metal interior. The lipstick tube is weighty and feels really luxurious in a modern way. Rush is very creamy, opaque, and comfortable to wear. I don't have issues with this formula bleeding outside of the lipline or wearing off unevenly.
NYX Butter Lipsticks sell for $6 and also come in 22 shades. NYX's Butter line is packaged very similarly to their Matte and Macaron lines - the opaque plastic top and bottom are separated by a clear band that shows the color of lipstick inside. The Butter line also features tubes that are the color of the lipstick. The packaging is functional, but feels cheap, even by comparison to other drugstore lipsticks. Pops is more sheer than Rush - the opacity is similar to a tinted lip balm. Pops is really comfortable to wear and lightly hydrating.
Are they dupes?
As you can see in the swatch photos, the color of both Rush and Pops is identical. Even so, they are not dupes - the formula is just too different. Pops has a more sheer formula, is balmy, and more slip in the texture, while Rush is more opaque, buttery, and creamy. Both lipsticks are lightly hydrating and comfortable to wear, but not long wearing. You don't need both, but I enjoy having both in my collection. I apply Rush when I get ready in the morning, and then take Pops with me for touch-ups because I can apply it without a mirror.
Overall: the color is 95% similar, the finish is 85% similar, but the textures are different.