Don' t call, they won't call back. Before you pay, ask to preview the list first. You can't sign up or browse the website. So when you go, tell them to get with the picture. Many SF landlords use this service.
Many places are available only online.
Search the database before signing up. AptRatings does not accept any money from apartments. This is no longer true. The following links were sent in by a the city of San Mateo's housing office. An informal network of landlords, tenants, housing professionals, investors and associations actively involved in rental housing.