About 3 months ago I started gradually running barefoot everyday. Since then I slowly transitioned from running in cushioned Nike Pegasus to running 55 miles a week barefoot. I run on grass for every run but can handle pavement for a mile or 2.
I can definitely tell that my performance and form has enhanced exponentially. It has built up more muscle around my ankle and calves and my old sloppy form corrected itself naturally. I now believe that running barefoot is how we are all intended to run, and those running in modern running shoes are not reaching their full potential.
The modern running shoes do nothing to help you, they make your muscles weaker and thus cannot sustain the level of exertion as long as you could running barefoot. It throws off your stride because the increased height between your foot and the ground makes a slight bend in the back and your posture isn't near as efficient, leading to weaker and runners more prone to stress fractures.
So I encourage all runners to stop running in modern shoes because it's not helping or beneficial at all. The Native Americans ran barefoot and they were great hunters and could run for very long periods of time. I wouldn't even recommend minimalist shoes either because they are expensive and you can just cut out the middle man and go straight to barefoot.
Don't run on pavement until you can do at least 30 miles a week barefoot on the grass. Once you can handle that you can try to run on the pavement as it increases the muscles and joints to be able to handle a much harder and powerful impact.
I pr'd recently in my 5k by 37seconds and during the race my feet were so strong from running barefoot that I was able to push off much harder and increase my stride.
The greatest misconception today is that running shoes help. We are being brainwashed into spending a ridiculous amount of money on useless crap that hinders how our bodies should naturally run, barefoot.