Hilton San Francisco Union Square is a centrally located hotel that offers modern amenities and a range of facilities, including a health club and a courtyard pool. Guests generally appreciate the convenient location and the easy check-in process, which tends to enhance their overall experience. However, some reviews indicate that cleanliness may not consistently meet expectations, with reports of inadequate room supplies and cleanliness issues affecting comfort. Additionally, there are mentions of noise disturbances from the surrounding area, which could impact sleep quality for sensitive guests. Overall, while the hotel has many appealing features, potential visitors should be aware of these concerns to manage their expectations.