It was stated by a few people that Five Fingers weren't meant to be running shoes. They're for hiking, going into rivers/lakes, climbing, or doing any other activity outside, usually on grass. It would be absurd to run a road marathon in them. Our feet weren't meant to run on concrete and most people don't think about that before they hop on the bandwagon with them. They're stupid and deserve their injuries.
Having said that, I love my Five Fingers and use them to SUPPLEMENT my running to help strengthen my feet and lower legs. In 3 months of wearing them AS MY NORMAL SHOES, NOT RUNNING SHOES, my posture improved so much that I grew an inch. Something must have become stronger in order for that to happen. I wasn't doing core or lifting at the time so I attribute it to wearing my Five Fingers.
If you have trails and grass to run on in them, go for it. Be careful about how much you run in them. I love running barefoot on nice SOFT grass fields. I also like running in my Five Fingers on FIELDS, not roads. As has been stated before, they weren't meant to be running shoes but people looking for an easy way to try and get fast picked them up and made them out to be like steroids. They got a lot of attention because there are waaay more slow people than fast people out there. Also, after a week or two most people prefer them to normal shoes.
I haven't had an injury since I started wearing them and I used to be injury prone. My team mates that try to run on the roads in them have several foot and knee issues and don't understand why they're Five Fingers seem to have failed them. I hate being able to say "I told you so" to them while they're sitting in the rehab room.
All-in-all, it's the people who get overzealous with them and get injured that make them look bad. Personally, I think they're a great tool to help supplement your running.