here is an interesting article I found about the effects of barefoot running. I still like my VFF & haven't had any injuries or issues from using them.
ARTICLE
I haven't been injured from the VFFs, but I did injure my ankle playing sports and have had to return to regular shoes while recovering. I believe in the concept, but they aren't very forgiving. I favor the VFFs, but I'm not a Kool-Aid drinker about it. They aren't for everyone, and need to be used intelligently.