I watched The Phantom Gourmet on Boston's NECN station for years. It was hosted by Billy Costa, who is also a DJ on the long-running KISS-108 morning show with Matt Siegel. After the show ran for eight years, producer Dan Andelman and his family moved the show to WSBK 38, another Boston station. Costa stayed at NECN and launched a new show, TV Diner. The Phantom Gourmet is a mysterious person (they won't say whether the diner is male or female) who goes around in secret and reviews Boston and New England eating establishments. The show gives the restaurants a grade. The show also features other reviews and features as well.
TV Diner is a little different. They feature a lot of chefs and go behind the scenes of restaurants. The do reviews too, giving a "plate" grade, but it's not as much of a focus as it is on the other show.
To say things are tense between the two shows is an understatement. Besides the typical tension you would expect from two similar shows in the same TV market, Costa is a little ticked that The Phantom Gourmet asks their guests (chefs, foodies, customers, etc) not to appear on the other show for a few months.