Creme Cup is a light to medium, slightly blue-based milky pink. There's still a bit of rosiness and warmth to it, and thankfully it's not as purple on my lips as my other cool pinks. I find it creamier and more comfortable on the lips than Shy Girl, which feels more matte and drying. Creme Cup has often been compared to Angel, the shade made famous by Kim Kardashian. From swatches online, it seems Creme Cup is a touch brighter and sheerer than Angel, which looks more cool-toned and pigmented. Though the two are very similar, being the pink lipstick tragic I am, I'm still curious about Angel, especially since you can only really gauge what a lipstick looks like by factoring in the natural pigmentation of your lips and your overall colouring.
l-r: MAC Creme Cup, Revlon Primrose, Revlon Strawberry Shortcake, Revlon Pink Pout, Australis Jive
Surprise, surprise. I have quite a few shades close to Creme Cup. The four other lipsticks are very similar (they're all about the same darkness of pink), with only subtle differences. Revlon Matte lipstick in Pink Pout looks to be the closest in colour, but it's drier, more pigmented and a touch purplish. Revlon Super Lustrous lipstick in Primrose is almost a dupe of Pink Pout, but cooler, a touch darker, and a bit more mauve still on the lips. Revlon Lip Butter in Strawberry Shortcake, like the Cremesheen formula of Creme Cup, is more sheer and moisturising than a straight up lipstick, but it's a brighter pink and less pastel. Australis Colour Inject Mineral lipstick in Jive is a darker, more muted rosy pink, whereas Creme Cup is lighter and warmer.
While I don't find myself reaching for Creme Cup that often, I like that it's a wearable baby pink that doesn't pull too purple on me (a perennial issue for these blue-based pink lipsticks I keep buying and being disappointed with). Despite how many pink lipsticks I own, I don't have anything exactly like Creme Cup. I like the warmth and milky quality that it has, while not being too pale, bright, dark or mauve.