Must admit I havent seen those vibram five fingers down here in New Zealand, do you buy them retail up in the US, or are they available only online? I do like the different textures that I walk on in barefeet, but I suppose for exercise/running etc they would be good, although barefoot running has become very popular down here (so has barefoot walking). They do look a bit odd, I must admit, and Im sure you'd have to get exactly the right size, otherwise they would be really uncomfortable.
The five fingers shoes are at some stores, it's best to try on a pair and get the right size then order the style you want online. You feel the different textures through the rubber sole but the sharp ones don't hurt as much. Like I walk on gravel barefoot and it is okay but with these on I can run on gravel. I love them so much I am pondering getting another pair soon. I just wish there was a waterproof one for wearing in the rain, or maybe toe-boots, lol:)