There are some variables here. Are you asking if it is a total scent containment product or if it reduces scent? I don't believe for a second that it eliminates all scent, my Dad's Bloodhound is proof of that. I do feel it can be an assett if used properly, along with effective descenting through showers and spray with no scent products along with a breath spray.
I personally do not have a lot of Scent Blocking clothing, instead I wear as little as needed on my walk in and then layer up when I start to cool back down in my tree. I wear a new outfit everytime I go out and wash my hunting clothes after each hunt and rarely get winded.
I often ask myself this question---"How many world record animals were killed by hunters wearing scent containment clothing"? I know in the deer world that most were killed before the stuff even existed