Great material. Great fit. I'm 6.4 and they sit about 5 inches above my knees. These are for slim to medium build calves. I sent them back because I am looking for a smaller heel, but even then the heel is only about an inch - 1.5 inches.
I have been eyeing these for months and contemplating whether or not I needed to spend the money, but they're Stuart Weitzman! You can't go wrong with him and his shoes. They will be around for ages! I did have to size down from a 9.5 to a 9. I hope to wear them with pants, but haven't tried that out yet.
I normally wear a 39.5 and got these in an 8.5 and they fit perfectly. They are super comfortable and a better/warmer/more stylish option than tights in fall/wintertime. I have pretty thin legs so I can't really comment on how much stretch they have.