Strawberries aren't normally labeled a superfood but the fact is that their antioxidant content ranks just ever so slightly below blueberries, raspberries, and blackberries. The red pigments in strawberries offer certain forms of antioxidants you will get less of in the blue and purple fruits.
ORAC Source
USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 - Prepared by Nutrient Data Laboratory, Beltsville Human Nutrition Research Center (BHNRC), Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA) - May 2010