A product's shape can be protected two very different ways, and the difference decides who wins. A design patent is an examined federal right that lasts fifteen years and demands no proof that anyone recognizes the shape; product-configuration trade dress is a use-based trademark right that can last forever but that a claimant can enforce only after proving the shape has come to signify a single source. This article compares the two regimes across every axis that matters in practice: subject matter, the functionality bar that both share, term, cost and speed, the secondary-meaning requirement that burdens product design, examination versus use-based rights, claim scope, infringement standards, and remedies, including the extraordinary total-profits award of 35 U.S.C. § 289. It explains why an expired utility patent is "strong evidence" of functionality that can kill a trade dress claim, and how a disciplined company sequences both rights over a product's life. A step-by-step decision framework and a worked hypothetical turn the doctrine into strategy that a judge, a practitioner, and a business owner can each follow.