Competitive advantage: Often overlooked, frequently misunderstood, and generally underappreciated, it may be the most important factor investors should consider before taking a long-term stake in a company. In this video, Motley Fool Co-Founder and Chief Rule Breaker David Gardner presents three critical aspects of competitive advantage -- brand, distribution, and vision -- and looks at companies that possess them in spades

Back in the late 1990s, many people underestimated Amazon (Nasdaq: AMZN), predicting that the company wouldn't last because anyone could come along and build a website that sold books and music. Boy, were they wrong. Similarly, these days, folks might not be seeing the competitive advantage held by online restaurant reservations company OpenTable (Nasdaq: OPEN), which boasts an incredible, perhaps impenetrable, distribution network. And how about the vision of a company like Netflix (Nasdaq: NFLX) and its visionary leader, CEO Reed Hastings, who's been "skating to where the puck is going to be" for as long as critics have been writing off his company as a dead-in-the-water DVD-rental service. Each of these characteristics is essential to long-term business success, and each can be categorized under competitive advantage, one of the most important valued assets a company can have.

Watch the video below.