Ride-hailing services, alongside public transportation (subway and bus), active modes (bike-sharing and walking), and private cars, are collectively reshaping urban transportation systems worldwide. However, the differences in user risk perception and functional positioning among different ride-hailing services, especially express and ride-pooling, are not yet clear. The study, conducted in Nanjing, China, designed two stated-preference questionnaires to assess the substitutability and complementarity of express and ride-pooling services. Four latent variables were introduced to quantify user risk perception: time risk, economic risk, service risk, and safety risk. The Integrated Choice and Latent Variable model used in this study is based on the Mixed Nested Logit model, which focuses more on the interdependence among different travel modes, as well as individual heterogeneity, compared with traditional logit models. The research findings indicate that in terms of risk perception, ride-hailing users have stronger service risk perception, weaker time risk perception, and weaker safety risk perception compared with public transportation users. Furthermore, compared with ride-pooling users, express users have stronger time risk perception and weaker economic risk perception. From a functional positioning perspective, ride-pooling services complement public transportation systems, while express services are preferred for long-distance door-to-door travel. Based on the research findings, this study offers a set of recommendations to support the sustainable growth of Transportation Network Companies (TNCs), guide government regulatory efforts, and explore opportunities for collaboration between the TNCs and government agencies, aiming to foster the robust development of urban transportation systems.