Apple, Berkshire, and Walmart All Have New CEOs. Which One Will Do Best? — Barrons.com

By Andy SerwerTalk about a changing of the guard.Three of America's flagship companies, Apple, Berkshire Hathaway, and Walmart, have new CEOs at the helm, each of whom, to one degree or another, is succeeding a rock star predecessor. How will these new guys fare, and which one would you bet on?For…