Actually a lot of guys use it. Its just that this topic comes up quite often and can be VERY polarizing. Some swear by it while others say its a scam. If you do a search you could find a bunch of threads on scent loc.
For what its worth, I own one set of Scent-Lok coveralls. They were a gift from my wife. While I don't know if I believe the effectiveness of the odor trapping carbon, I know that it is a well made garment. I use it for that reason. When using it I make sure I follow the same scent control regimen I do when wearing non scent containing garments. I have a friend that won't hunt without the stuff. He swears he sees more and bigger deer now. He must leave them alone though, his results are no better!