I bought these for my wife. She a teacher and has to help kids at the crosswalks before school - even in the winter. She loves to wear these under skirts as they are warmer than regular leggings and she can also wear them under her slacks for particularly cold days. They are silky smooth, warm, and don't make her legs look "puffy." The price was great so I got her a second pair.
Only down side is the "long-john" type seams on  the butt. It's a trade off for the warmth, I suppose, but she won't ever wear them without a skirt to cover those seams.