Buyers must prioritize Frequency Band Compatibility (e.g., Band 1, 3, 7, 20 for Europe or Band 2, 4, 5, 12/17 for North America) to ensure the device matches local carrier frequencies. Key performance metrics include Gain (measured in dB)—where a minimum of 65dB to 70dB is required for residential/small office use—and Output Power (dBm), which determines the internal coverage area. Additionally, look for Automatic Level Control (ALC) and ISO 9001 certified manufacturing to ensure long-term signal stability and hardware reliability.