Check out this article from the Wall Street Journal, How Can You Make Running Less Painful?. It actually RECOMMENDS Xero Shoes!
Or see this post about what doctors from the American College of Sports Medicine recommend.
Here’s the short version:
The American College of Sports Medicine… recommends shoes with a heel-to-toe height differential, or drop, of no more than 6 millimeters, or about a quarter of an inch… buying shoes that are neutral, meaning without extra arch support or rigid motion-control components. The shoes should have enough forefoot room that runners can wiggle their toes easily and shouldn’t have excessive cushioning.
If you think that describes Xero Shoes, you’re correct.
You may also want to check out the Freakonomics podcast about minimalist and barefoot running, These Shoes are Killing Me, as well as Harvard’s Dr. Irene Davis’s “Join The MOVEMENT Movement” podcast interview or her interview, “Has our Footwear Outgrown Our Feet?” (check out what she says starting at 41:50!)