The differences between urban and rural B&Bs should be emphasized, which is critical for the sustainable development of the B&B industry. This study identified and compared the topics that customers were concerned about for urban and rural B&Bs in Beijing by analyzing 13,241 online reviews obtained from the website Ctrip. The results showed that customers focused on 10 common topics: “room”, “location”, “host”, “experience”, “surroundings”, “facilities”, “service”, “design/style”, “value”, and “entertainment”. However, the importance of each topic varied between urban and rural B&Bs. Customers paid more attention to the room. Urban B&B customers were more concerned about location. The convenience of urban B&Bs was more prominent than that of rural B&Bs, especially in terms of public transportation and commercial services. While rural B&B customers were more concerned about experience, service, design/style, and entertainment. In addition, the “host” is the most crucial and influential factor in the development of B&Bs. This study made contributions to customer perceptions of B&Bs from a comparative perspective and enriched the understanding of the characteristics of urban and rural B&Bs. In the part of practice, this study might provide enlightenment for B&B operators and local governments to take measures for B&Bs sustainable development.