ColourPop Notion is a slightly cool-toned, very dark berry with a semi-matte finish. It is a permanent lipstick that retails for $6.50 and contains 0.11 oz.
ColourPop Notion Ultra Matte Liquid Lipstick ($6.00 for 0.11 fl. oz.) is a deep berry with subtle, warm undertones and a mostly matte finish. This shade took an hour to dry down for me! The majority of the color dried down within a minute or two, but there were parts of it that stayed shiny for an hour. It had mostly opaque color payoff, and the texture was thin but fluid and spread easily across the lips, so it was a cinch to get even coverage out of the formula. The color lasted for eight hours but was drying over time. ColourPop Darling (LE, $7.00) is lighter (90% similar). MAC Fallen Angel (LE, $21.00) is lighter (90% similar). MAC Sumac (LE, $20.00) is glossier (90% similar). Tarte Acid Wash (P, $20.00) is less glossy (95% similar). MAC High Drama (P, $21.00) is warmer (85% similar). Makeup Geek Rocker Chick (P, $12.00) is lighter (85% similar). MAC Oh Lady (P, $21.00) is lighter, brighter (85% similar). ColourPop Alchemist (P, $7.50) is lighter (80% similar). Pat McGrath Deep Orchid (P, $38.00) is lighter, glossier (80% similar). Smashbox Femme Fatale (P, $21.00) is lighter, brighter (80% similar). Make Up For Ever M501 (DC, $22.00) is lighter, brighter (80% similar). Chanel Muted Fuchsia (124) (P, $40.00) is lighter (80% similar). See comparison swatches / view dupes side-by-side.
FURTHER READING: Formula Overview, which is a detailed review of the range as a whole.