After having one pair for a few months, I went back and bought two more, in different lengths and colors. They are made incredibly well, don't sag in crotch like cheap ones.
I first purchased these in a medium (I am 5'4" and typically wear a size 6), because the sales person recommended a medium and told me they run small. They seemed fine until I started working out in them, but I found they sagged and needed to be pulled up constantly during yoga and spin classes. I'm am trying the smal size now. They are nice looking and the fabric feels great, so I hope the smaller size does the trick.
Love these leggings! Not only do they feel great, but they look fantastic. I'm curvy on the bottom, but feel that these hug in all the right places. The waist band is also forgiving, which is great when you wear tighter workout tanks on top. Highly recommend!