While Johnnie Walker and Jack Daniel’s are both excellent spirits, they each bring different characteristics to an Old Fashioned. Johnnie Walker is a Scotch whisky, which is not traditionally used in an Old Fashioned. Using Scotch can introduce smoky and peaty flavors, offering a unique twist to the classic cocktail. This variation can be appealing if you enjoy the distinctive notes of Scotch, but it deviates from the traditional profile that emphasizes the sweetness and richness of bourbon or rye whiskey. On the other hand, Jack Daniel’s is a Tennessee whiskey, which is closer to the traditional base for an Old Fashioned. Its smooth and slightly sweet flavor profile makes it a suitable choice for this cocktail, providing a balanced mix with the sugar, bitters, and citrus garnishes. While not as commonly used as bourbon or rye, Jack Daniel’s can create a delicious and approachable Old Fashioned, especially for those who prefer a milder whiskey flavor. Ultimately, the best choice depends on your personal taste preferences and whether you’re aiming to stick to tradition or experiment with different flavor profiles.