coproate v/s individual branding

Yum Brands own KFC, Taco Bells, Long John Silver's and Pizza Hut (http://www.yum.com/about/brands.asp). But common people do not know Yum Brands as a company. Whereas they use this individual branding strategy, firms such as Apple and Kellogg use corporate branding where every product is sold with the corporate brand tag (corporate branding). Which of these branding strategies is better? Corporate branding has advantages that it enables more efficient communication to consumers, employees, investors and channel partners. But it is also risky. If one product fails, it carries its effect on all the other products. For e.g. if next Apple iPhone version is a technological failure then people will shun all the Apple products. But when rats were spotted in Taco Bells kitchen in NYC, people did not think twice while going to Pizza Hut. So, which strategy rules?