I switch between cast iron and stainless steel. Tomato sauces and other acidic foods/sauces eat away at the seasoning on the cast iron, so that is where the stainless comes in handy for me.

The stainless is also a lot easier to clean and maintain.

They both need preheating to effectively become non-stick, which has caused my ADHD ridden brain to mess up both of my pans. I turn the stove on to preheat, walk away to do something else, and forget about it. The cast iron has had its seasoning burned off, and required a lot of work to get it back in shape. The stainless now has a bulge on the bottom, making it take much longer to preheat, and is now wobbly. This is just a personal flaw lol