The Fitness Center at San Francisco Marriott Union Square
San Francisco Marriott Union Square's fitness center is endorsed by reviewers writing for major publications. Out of 5 reviews that we monitored, 3 mentioned the fitness center, like Oyster, Gayot and Star Service.
San Francisco Marriott Union Square 
Oyster
Gayot
Star Service
Oyster "Near the designer shops and theaters in Union Square, the 400-room San Francisco Marriott reopened after renovations in 2009 to show off new guest rooms and a new fitness center"
Gayot "Guests also have access to a state-of-the-art fitness center"
Star Service "The hotel has an excellent gym but no pool or whirlpool (ask nicely, and you may be allowed to take a tip free of charge at sibling Marriott Marquis)"
