I love these jeans.  Very comfortable, very flattering and fit perfectly.  I had a pair of the 512 before and didn't remember a slimming panel.  Realize now, that is because the panel is not really noticeable, actually the same fabric as the pocket lining. It is not constricting, but being cotton, doesn't have the stretch (just where you don't want the the stretch).  The only thing I don't like about these jeans is that the side seams are just regular seams, not the double stitched seams.  But I will exchange that for jeans that are so otherwise flattering.  I have spent a lot more for jeans and not felt 1/2 as good in them.  I purchased the midnight star, and plan to also get the lighter shade.