Urban Decay Bittersweet is a warm purple with a satin finish that is discontinued and retails for $22.00. In comparison, Revlon Luminous Lilac (018) is a warm purple with a luminous finish that is permanent and retails for $9.99.
Revlon Luminous Lilac (018) is 85% similar — it is more shimmery, less pigmented, cooler, glossier.