Buyers must prioritize the Category (Cat) rating, which determines data throughput. For low-power sensors, LTE Cat M1 or NB-IoT is ideal, while high-bandwidth applications like video surveillance require Cat 4 or higher. Additionally, verify frequency band support (B1, B3, B7, etc.) to ensure compatibility with the target region's carriers. Ensure the module supports GNSS (GPS/GLONASS) if location tracking is required, and check for industrial-grade temperature ranges (-40°C to +85°C) for outdoor or factory environments.