When evaluating gas smokers, prioritize heavy-duty steel construction (minimum 1.5mm thickness) to ensure superior heat retention and durability. The BTU rating should be sufficient for the cooking area, typically ranging from 12,000 to 20,000 BTUs for vertical cabinets. Look for dual-door designs which allow for adding wood chips or water without losing heat from the main cooking chamber. Additionally, ensure the unit features adjustable dampers for precise airflow control and high-quality door seals (such as fiberglass or silicone gaskets) to prevent smoke leakage.