Washington, DC--Challenged to deliver the best customer dining experience in the Washington, DC, area, franchisees operating 109 Burger King restaurants signed on to dramatically improve food quality and friendliness within three months ending January 31. According to Burger King, during the three-month period, 57 percent of the 109 restaurants participating earned and maintained mystery shop average scores in the 90s. Managers for restaurants with the best overall mystery shopper scores were awarded chances for prizes, including cruises and shopping sprees. -PRNewswire