Sounds like they're talking about fit and finish, not how well it wears in the real world.
From Apple's site:
"Never before has this degree of fit and finish been applied to a phone. Take the glass inlays on the back of iPhone 5, for instance. During manufacturing, each iPhone 5 aluminum housing is photographed by two high-powered 29MP cameras. A machine then examines the images and compares them against 725 unique inlays to find the most precise match for every single iPhone."