Be prepared for the heat. The cook space gets pretty toasty when you're blasting up to six power burners, plus a griddle or grill, sometimes all at once. Proper ventilation helps, of course, but you'll also want to buy heavy-bottomed pans that are several inches larger than the burners so that the heat isn't just bypassing them. Keep in mind, too, that the heavy cast-iron grates that are standard on most of these ranges radiate more heat than traditional steel grates and can take an hour or so to cool off completely. Handle them with caution during cleanup.
Test it. Look for a retailer that has the floor models connected to live gas so that you can give them a test drive—and not just by turning them on. Boil water, fry an egg, or try melting a bar of chocolate and keeping it glossy instead of having it turn grainy. Some showrooms also host chef demos on pro techniques, such as sautéing asparagus on a griddle or making a roast in a steam oven.