- Burger King has debuted its own version of rival McDonald's Big Mac .
- Burger King says the new burger, called the Big King XL, has 175% more beef than the Big Mac.
- Burger King is giving away Big King XL burgers for free to customers who place a $3 minimum order on Grubhub .
Burger King is giving away free hamburgers to celebrate the debut of a new sandwich, the Big King XL.