In the interest of full disclosure, I bought an insulated scent-lock coverall a few seasons ago because it was on sale at a ridiculously low price of $120 (at the time, I actually had no idea it was a scent lock suit). I must say that when it's pretty freakin' cold outside, that suit has kept me toasty warm.
That being said, I see just as many deer when wearing jeans and a jacket in the fall. The claims of being scent-free by wearing scent-lock is bogus, in my experience. It does, as I mentioned already, keep me warm though.