We recommend Angostura Bitters. Made from a recipe of herbs and spices, Angostura Bitters add depth and complexity with hints of cinnamon, clove, and gentian. Their well-balanced and aromatic profile perfectly complements the Whiskey and Sugar in an Old Fashioned.
Overall, Angostura Bitters are more versatile than Orange bitters. But of course, which type is down to personal taste.