When evaluating PVC Coated Nylon, you must focus on the denier count (e.g., 420D, 840D, 1000D) which determines the base fabric's strength. The coating thickness (measured in mm or gsm) is critical for waterproof performance. Ensure the supplier provides data on tensile strength, tear resistance, and adhesion levels to prevent the PVC layer from peeling under stress. For outdoor applications, specify UV resistance ratings and cold-crack resistance if the product will be used in low-temperature environments.