I buy (as mentioned above) from a local deer farm near my parents. I have had marginal success with it in most cases using a drag/drip method. I have had a few bucks walk right down the scent drag but I would say out of all the years I have hunted this has only been a dozen times or so. Prior to being referenced to a local farm I was using Code Blue and to be honest never had any luck but this could be partial to what the above poster mentioned as I was not familiar that was the situation with "Store Bought" brands.
Again I would say I only use it a few times out of the year though so my experiences are only limited to those few days I do and I don't think are the greatest representation I wouldn't mind hearing someone chime in that is an avid user. Also as a point of note I have used the older "Scent Candles" which put off a crazy amount of scent and probably out of the 6 sets I burned them for I had buck actively come in on 3. I was pretty impressed but have never got around to trying them again.