I've been using spanx for a couple years, and these are my faves. they fit perfectly and slim my stomach, and make my thighs amazing in tight jeans, and my torso amazing in form-fitting dresses.
BE AWARE: They keep your stomach/butt from protruding. that is all. if you have aproblem with them rolling up or down, you ordered them too small. period. I get the feeling afew people ordered these expecting a magic wand effect. uh, no. They are slimmers, not corsets. if you are very overweight, don't expect them to make you skinny.