I am 5'4 and around 130 lbs, and the medium size fits me fine.

I chose the 'latte' color, which is a bit more khaki/yellow than it appears in the picture.  I usually wear them under a skirt or dress, because on their own, in the wrong light, it looks like I'm not wearing any pants.  I like them enough that I'm buying a few more pairs.

The fabric is comfortable and has kept me pretty warm with just a skirt and boots in 30 degree weather.  Overall I'd definitely recommend these to a friend.