Good rib racks such as the Weber model hold the slabs upright with enough airspace between them to allow airflow and smoke penetration. Bad rib racks hold the meat too close together so they don’t cook properly (see my article on rib racks).
Weber 6605 Original Rib Rack
Where to buy (buying from this supplier supports this website):
Meathead, BBQ Hall of Famer - Founder and publisher of AmazingRibs.com, Meathead is known as the site's Hedonism Evangelist and BBQ Whisperer. He is also the author of the New York Times Best Seller "Meathead, The Science of Great Barbecue and Grilling", named one of the "100 Best Cookbooks of All Time" by Southern Living.