re: How do I cook a ribeye on the stove/oven?

Cast iron is a much, much denser material. It's going to retain heat better (the heat won't drop as much when you put the steak in) so you'll get a better sear. It's also going to be much more even in that there won't be hot spots in different areas of the pan.

Also, once seasoned properly, it's damn near impossible to get stuff to stick to cast iron. Even eggs.