I use a carbon suit and I think they work, if you also sprayscent killer stuff onany exposed areas, especialy your head and hands, as well as sprayaround your stand, on your equipment, etc.

Last year I had a group of six does sneak up on me from behind the day after a rainfall (which made the leaves very quiet) while I was intent on a buck emerging from a thicket just downhill and upwind from me. The does came from uphill and downwind and my stand was only about 8 feet off the ground. At one point the entire group was within 15 yards downwind of me without scenting me.

I think the stuff works!