I ran 10.3 miles in them this morning. The Five Fingers are comparable to moccasins only they're made of high tech rubber rather than low tech deer skin. But they're not foam rubber like running shoes. They're a layer of nylon and rubber that fit your feet like a glove.
My run this morning had it's positives and negatives. On the positive side, I ran at an average pace of 9:18/mile. That's my best time this marathon training season for this length of run. I give some credit to cooler weather. But it was still around 72 degrees this morning and very windy.
On the negative side, I run in pre-dawn darkness for my long runs. Since you can feel every bump and pebble in the Five Fingers, avoiding them is difficult in the dark. My feet are more tender this morning than any run I've done in them to date. So I don't know if I'll use them for any more long runs in the dark. Other than that, my legs feel fine.
Bottom line is I love running in these things. But I won't do all of my training in them and I probably won't run any more runs exceeding eight miles without my New Balances. But next year, I may run an entire marathon shod with the Five Fingers.