Presto Pressure Cookers
Regardless of materials, aluminum or stainless steel, a safe modern pressure cooker will have three independent safety valves to ensure that excess steam is allowed to escape, keeping control of the pressure within the cooker. Most also are built with as safety mechanism that prevents opening the lid while the cooker is under pressure. A last key to insure safety is keeping all of these mechanisms and the gasket clean. See any Presto pressure cooker for a good example.
Ultimately, the choice is the consumer’s. A choice based on the needs of a kitchen, a household’s budget, and the style of the cook. Cooking with a stainless steel pressure cooker, or even an aluminum one, continues to be an efficient, effective and speedy way of cooking a nutritious meal.