MAC Turn to the Left is a cool brown with a semi-matte finish that is permanent and retails for $22.00. In comparison, YSL Ambiguous Chestnut (216) is a warm brown with a natural finish that is permanent and retails for $39.00.
YSL Ambiguous Chestnut (216) is 90% similar — it is more shimmery, darker, warmer, glossier.