Buyers should prioritize multi-constellation and multi-frequency support (GPS, GLONASS, Galileo, BeiDou) to ensure stable signals in obstructed environments. Look for a high number of channels (typically 800+) to improve satellite tracking efficiency. The initialization time should be less than 10 seconds with a reliability rating of >99.9%. Additionally, verify the radio power output (typically 1W to 5W) to ensure the internal UHF radio covers the required working range, usually 5km to 10km in typical conditions.