Vibram Five Fingers are heavier than other options, extremely hot, and leave your little toe open to potential injury on roots, rocks, etc. Also, they can beat up the bottom of your feet if hiking for prolonged miles on rocky terrain. To be honest, I do not see where they fit into my gear kit at all. For those who are into barefoot running philosophy, they do have a place in some situations.
Last year I did a 60 mile hike, which included many miles of scree, rocks, lava beds and the like. I wore the lightest racing flats that I could find, Asics Piranah, at about 5 oz each. The bottom of the soles were completed shreded at the end of the hike. The bottom of my feet were a little sore, but not too bad.
This past weekend Craig Wisner and I did a similar hike. Craig wore MT100s, and I wore Sacouny Shay racing flats. Similar in weight, but the Shays have formed spikes in the soles. I think the Shays performed a little better on hard snow pack. We probably did at least 10 miles in snow. We both brough plastic bags to use a water proof socks, just in case. We did not need them, as our wet feet quickly dried, and moving all day, our feet we warm enough, actually sometimes it felt good to be walking in cold snow. I did injur the ball of by left foot, when I land hard on a pointed rock on day 1. We probably did at least 30 miles on very rocky terrain.
I can't speak for Craig, but going more than a couple days on this kind of rocky terrain is probably too much for this kind of minimal shoe.
I thought that the Shay's would do better than the Asics... and they did, as the soles are still in great shape. But on the 3rd day, the right Shay shoe suffered a construction failure, causing that foot to over pronate, more than if I were walking barefoot. This could have been caused by me changing my walking due to the injury, as I was favoring my left foot, and hiking with more impact for 45 miles on my right foot.
So in the future, I am going to stick with my Saomon XA Pro 3D's for hikes of this magnatude.