I recently had the opportunity to try on various of the Vibram FiveFingers shoes, and found that they were not quite what I was expecting. To give you some background, I walk barefoot a lot, and hike in flip-flops. I do not run. My main interest in 'Barefoot Running' shoes is primarily having something comfortable to wear at work, although I expect them to be appropriate for hiking if the situation calls for it. The upshot of this is mostly that I can't tell you how these would do as running shoes, which is a pity, as that is one of their main uses. However...
Obviously, the primary item of note with these shoes are the toes. I had assumed that I would find having the toes separated rather uncomfortable, as the shoes do spread out the toes slightly more than usual. It turns out that this is not at all uncomfortable -- at least not for the 30 minutes I spent trying on shoes. I would not hesitate to go hiking in Vibrams, at least not for worry of toe discomfort.
On the other hand, the frequent claim that these shoes are like gloves for the feet is pretty clearly false. They do not allow you to move your toes freely; they do allow for great freedom for the balls of your feet, giving you a lot more freedom in movement than most traditional shoes. However, you cannot curl your toes to any significant degree, and they do not conform closely enough to your toes that they would allow you ease in rock-climbing. (Obviously, this will depend somewhat on the size and shape of your toes, but the designers had to err on the side of caution; the toes are soled, and therefor have a limited ability to conform to your toes.)
The other note worth mentioning is that while the sole is very flexible and gives you a lot of freedom, it does have a comparatively firm arch. Not to the point where it gives obvious arch support, but it does interfere a bit with flexibility, in contrast with the otherwise extremely flexible sole. This is not a factor that would prevent me from buying the shoe, but it was a bit of a surprise.
In the end, I did not buy a Vibram FiveFinger (despite an excellent half off-sale on a selection of very nice shoes) because they would not be considered "professional" by my employers, and I really don't have a need for a shoe outside of work. Had I been in the market for an athletic shoe I would have gone with Vibrams as long as they were competitively priced (they generally are), but I would not have preferred them over other barefoot runner shoes based on the separate toe feature.