I can't recommend them strongly enough. I was told about them a couple of years ago by a fell runner who'd been having achilles tendon problems and had first been told to get more 'supportive' shoes (i.e. more conventionally padded ones that fell guys usually use). But after the problem went from niggle to pain, he tried another physio who recommended the opposite - barefoot running. Mike built up gradually from just walking about barefoot and then using the Vibram Fivefingers (which he'd had to order from the States) on short jogs. He's now regularly running 20 miles or more in them. I haven't run that far but I did walk the 14 miles of the Kentmere circuit in the Lake District in them
without a single blister This for me is a triumph as any other footware blisters me somewhere on a walk of any distance.
Building up slowly is the key as the first time you walk off road, especially uphill, you notice how much more strenuous it is for your feet - your toes actually ache with the unaccustomed effort. Your achilles/calfs work harder keeping your heels up and your ankles strengthen and improve balance as you're usually putting less of your foot on the floor. There's less pronation as you don't roll from heel to toe and I've noticed that my arches have improved in strength and flexibility - getting back to what they were when I did ballet as a youngster
- which improves their shock absorbing function when running.
I'm on my second pair now with the first pair relegated to about the house when my feet are cold. But they must have done a fair amount of mileage and they're still great for yoga - if you don't have a sticky mat to hand, they give great grip on any surface without spoiling the ability to use your feet properly in the poses.
All in all, I tell everyone with feet/ankle/knee problems to try a pair but start gently. And if you're a heel-striking runner, check out POSE running as you'll need to learn to run properly.
I guess you could say I'm a fan
I could also add that my sister is doing the Nice Ironman in June and is seriously considering using Fivefingers instead of running shoes in the marathon section - she's a POSE runner too, as are many of the top triathletes as it's more efficient and involves less hammering of the body than conventional running.