The Restaurant at San Francisco Marriott Union Square
San Francisco Marriott Union Square's restaurant is referenced by professional travelers. Of the 5 publications that we monitored, 3 referenced the restaurant, such as Fodor's, Gayot and Star Service.
San Francisco Marriott Union Square 
Fodor's
Gayot
Star Service
Fodor's "The Restaurant serves breakfast, lunch, and dinner daily"
Gayot "American, the on-site restaurant, is open for breakfast, while bin480 serves cocktails and small-plate appetizers for lunch and dinner"
Star Service "A small informal restaurant (breakfast room until 11 am, meeting room beyond that) provides bountiful but expensive breakfast buffets only, while the main dining room focuses on lunch and dinner"
