These socks are thin enough to fit comfortably in my Five-Fingers, thick enough to help prevent hot spots on my feet, and their use makes washing my shoes less frequent.  I like that they don't stick up above my shoes. Also, my feet slide more easily into my shoes when I wear the socks. They take some practice putting on as my little toe often likes to slide in next to its neighbor.

I've had them for about a year and they have held up, no holes in the socks, and although they have thinned in the balls of the feet area, they are still in pretty good shape.  It's too bad they are rather expensive for socks but overall worth it.