So, as I've mentioned before, I wore my Vibrams Five Fingers to Philmont. As I've also mentioned before (although I cannot find that post now, so perhaps I mentioned it in a backpacking forum?), there seemed to be precious little information about how well they work as shared by the people who actually wore them and plenty of shared opinions by people who saw others wearing them and had decided that it was stupid no matter what the wearers had said. So, I wanted to chime in with my .02, having done it first hand.
Overall, they were magnificent. Not one blister, no twisted ankles, no particularly sore feet. Actually, for most of the trek, my feet were the only things that weren't sore. The rest was poor chiropractic care, improperly adjusted pack, and my general propensity to run into things. I will be wearing these on the Pinhoti, the AT, and, if I ever get back that way again, these puppies are coming with me to Havasupai.
Lightweight. I wore my new ones on the trail and took my old favorites for in camp. So lightweight!
Easy on/easy off. This is particularly helpful when you're getting and out of your tent, but it's an all-around benefit.
Excellent feedback. I knew before I transferred my weight to my forward foot whether my footing was sure enough to support me. I truly suspect this impacts the likelihood of twisting an ankle on the trail, protecting your feet by preventative measures. So even with the marked lack of ankle support, these are my favorite trail shoes.
Comfortable. Although I took my old pair to wear in camp, I never felt the need to take off my trail shoes once we got to camp. There was one night that we had a particularly damp campsite (at Pueblano) and we had crossed a stream little earlier, so the trail pair weren't dry by morning. I just clipped them to my bag and hiked that day in the older pair.
Quick drying - we crossed so many streams, and I could just walk through them and keep going without having to stop to change out socks or even shoes. With the exception of the freakishly moist camp mentioned above, they always dried quickly.
Bouldering. Ohhh, this was fun. The Tooth of Time, and the trail to the ridge were SO easy with the Vibrams. I tucked my poles away and scrabbled around like a rock squirrel, even with my pack on. It was glorious. Love. These. Shoes.
The stench. Lord have mercy, these things stink! I would say they stink after 10 days on the trail, but they stank at the end of the first day. WHEW!
Wet clay - if you go during monsoon season, you're just going to ski down the switchbacks. Use your poles and relax for the ride. I pretty much skied all the way into the Ute Gulch Commissary. That was a little bit harrowing, but once I realized I wasn't going to die, it was fun. I don't know that hiking boots or anything else would handle the slick bentonite clay any better, but in the spirit of full disclosure, I did want to mention that this was A Thing.
Going downhill, fully-loaded, fast. The last day of our trek, we left Upper Clark Fork and trekked 12.5 miles out of the canyon, over the Tooth of Time, and down the Trail of Tears. Because our crew did not believe in getting up and out quickly, we were on the ridge with the afternoon monsoon storms at our backs coming down the Trail of Tears. You do not want to be on that slope in the middle of a thunderstorm, where the tallest thing around is you, and we Advisors felt the need to get the boys off the ridge pronto. So we absolutely booked it down that last few miles. With a fully loaded backpack. My toes were a bit grouchy after that leg. Not enough to negate the benefits, but again, A Thing. And if I'm going to share my experience, I want to share all of it.
I don't normally wear socks with my Vibrams, but I did buy some Injinji sock liners for this trek. (Not an affiliate link. I just love being able to include pictures.) They made the shoes a titch tight, since I hadn't bought them with liners in mind, but not uncomfortable and the shoes stretched quickly to accommodate the difference. They kept my toes warm in the damp, cool mornings, and they dried fairly well. Plus, they feel good.
Someone at Base Camp mentioned Swiss Socks. I'd like to try those out at some point, too.
If you do plan to wear Vibrams on a trek of any kind, get them well ahead of time. Train in them. Lounge in them. Wander in them. Wear them, break yourself in to them, get to know them. The learning curve is longer than with Just Any New Shoe. Once you've got the hang of them, though, they're very accommodating and straightforward. Know how they work for you, and what you can expect from them in performance. Then get a new pair (I went with the same style, same size, just to limit the variables, but I don't know that it mattered in performance) for the trail.
I hope this was helpful.