I have been using one now for three deer seasons.....keeping in mind that the last two years due to military commitment, my hunting was uber limited.
The first year I had it I was in KY on leave, I had several does walk downwind of me without a clue.....a few minutes later a buck came from another direction.....had they spooked and blown, I might not have seen that buck....but for sure the does were downwind of me and they didn't have a clue.
Since I only hunted one week I sent my system to my buddy in NY to try out and tell me what he thought. He said he had deer downwind of him.....and they didn't blow, or stomp, but acted confused.
Last year I got to hunt a bit in KY and TN. I didn't document how many times deer came from what direction, I just remember that I killed 3 bucks, 2 in TN and 1 in KY.
This year, opening weekend in KY, I hunt a draw, the wind was blowing into the draw, kind of where I thought the deer would come from, sure enough, it was 4pm and I had a deer blow....but I hadn't put my system up, I set everything up and hoped. About an hour later, I heard a deer blow super close.....spooked me. I stood, 5 minutes later a doe came through.....I am guessing they smelled residual from when I walked in.......she came through with a fawn.....she seemed confused, but she fed within 20 yds of me. The next night I got set up and within 5 minutes being in stand, I had a forky and his sister come through, they fed around me forever before I shot the doe. Again, they seemed confused at times.
Last weekend I had does come through at 40 yds down wind...wasn't a strong wind....they didn't have a clue that I was there.
Tonight I turned to look downwind....and I saw a deer....and two seconds later the deer blew and two deer departed the same area in opposite directions.
Do I think it works, yes, do I think there are variables I don't understand yet, yes.....like wind speed, how high I am in the stand. For the most part I pay attention to the wind and set up accordingly.