I preferred the Burger King Whopper over McDonald's Big Mac.Erin McDowell/Business InsiderOne could argue that fast-food chains are defined by their signature burgers.I compared the Big Mac and the Whopper with cheese to find out which burger came out on top.Burger King's Whopper impressed me with its flame-grilled patty and fresh toppings.Practically every fast-food chain has a signature burger … and some are better than others.I decided to compare the most famous burgers from the two biggest burger chains in the US: McDonald's and Burger King.I tried the McDonald's Big Mac and the Burger King Whopper with cheese to determine which classic fast-food burger is best based on taste and value.Every fast-food chain is striving for value in 2025, amid price hikes and a competitive market with other brands.