My personal take is that it may help if you are a treestand hunter from back East who drives his 4 wheeler into the field, stops 100yards from the stand, changes into Scent Loc clothes and then hikes the grueling 100yards over flat ground to climb into his stand.
Seriously, it may help out some on the first day or so of your hunt, especially if it is not too strenous. But after a few days of hunting hard your sweat and BO funk will infiltrate the suit rendering it no better than standard garmets. Plus there is scent everywhere, on your hands, your hair, your pack, your truck seat, your breath, etc. There is no reasonable way to control your scent 100% when out on a long hunt in the sticks. And there are no dryers to reactivate the carbon. I think a good washing with scent control soap works just as well as Scent Loc clothes. I have also known Scent Loc stuff to make hunters lazy about hunting the wind. They think it will allow them to make mistakes. Not true. Ultimately, hunting the wind is the only real solution, and more often than not, mountain winds betray you. That's bowhunting.
Scent Loc may help under ideal conditions, but it sure isn't fool proof.