The heavy ridged steel grill pan emulates the charcoal grill and is now widely used because it delivers intense sealing heat with the added benefit of searing lines on the outside of the food being cooked, to present an attractive cross-hatched effect called quadrillage by chefs.
The grill pan is ideal for things like steak and chops, but only if the ridges stand proud from the base of the pan, otherwise the food will fry rather than grill. The heat of the grill pan can, however, be too fierce for some delicate foods. The overhead grill, for example, is better for cooking whole fish or fillets of, say, Dover sole. In an ideal world you will have both in your kitchen. After that, it’s horses for courses; and, of course, when cooking horse a ridged pan is better than an overhead grill.