Cast Iron is a poor conductor of heat; which means it's slow to heat up and slow to cool down. But this self-regulating nature makes cast iron a preferred material for dutch ovens, fry pans, griddles and grill pans. These pieces are exceedingly durable and resist warping, denting and chipping.
Cast iron cookware is available in its natural state or enamel coated and both cook similarly but there are other notable differences. Natural cast iron costs substantially less, but it requires the user to apply a "seasoning" coat to protect it from rust. Aside from preventing rust, seasoning creates a wonderfully nonstick interior, and it has rustic/iconic good looks.