This isn't too bad and stays on pretty well but after some time the ribbing can dig into your skin at the top and bottom and leave red marks.  I wear it with a cami underneath and that definitely helps if I wear it long.  Size wise I have a 28" waist and I got the small which on the first set of hooks is tight but not uncomfortably so.  It does a good job staying where it is and doesn't ride up or down, but it is not totally seemless nor does it always lay completely flat so itcan be seen under a tight fighting top or dress.