"Since Fleet Feet started selling Vibram FiveFingers about three years ago, Phoenix said they’ve been difficult to keep in stock. As part of the minimalist trend, these shoes are sought to strengthen feet and different leg muscles, but should be used with caution.
"'A lot of people come in here with the perception that "I’m going to run two hours in these," and you just can’t do it,' she said. 'You’ve got to use it as a tool to strengthen before you do any serious running. I’ve heard of people running marathons in them, but they’re really an efficient runner and they can pull it off.'"
Running barefoot or in minimalist shoes makes you efficient. Sneakers allow sloppy form, barefoot-style punishes it.
She's right that you're not going to be able to run two hours right off the bat, but after an adaptation period? No problem. And your legs (and feet!) will feel great afterward.