Steel is nice but you'll find that cast aluminum is thicker, heavier, & holds the heat longer & more evenly! My ancient cast aluminum Mirro pressure cooker doubles as a candy cooking pot come Christmas!! For candy you need a really heavy thick pot to prevent scorching or outright burning the candy. Pressure cookers are sooooo versatile!!!
P.S. If you do accidentally burn the beans or something else, scrub the pot out as best you can, then boil the pot with either baking soda/water or dishwasher soap/water for an hour or so till the stains are gone. Keep an eye on the water level, & test the stain with a scrub brush periodically. This really works!!!! That's dishwasher soap, NOT dishwashing liquid! I prefer the baking soda, however!!