Decoys work in situations when you are in an opening and gives the tom a visual to come to. If he can't see them, they don't do any good. If he can, it is all up to him what he is in the mood for. Like other posters have said, there is no one good decoy setup. They all may work in different situations.

Where I hunt, it is mostly open fields and the turkeys like to roost in a small wooded area close to the edge of the field. I normally use a single feeding hen and a plain jake decoy. I try to setup my decoys so that they can visually see them in the field from the roost. On three different occasions, I have had toms fly from the roost straight to my decoys.

This year, I had four gobblers land in front of me within shotgun range.

My second gobbler Would not come to my decoys and even came within 50 yards at one point and walked away. I could tell he wanted the hen but I'm not sure if he saw me or if he was scared that the jake decoy was there. An hour later he came to me anyways and I got a 15 yard shot.

I have also had other situations where toms come in and will not come in close enough. Again, not sure if they are scared of the jake decoy or just being cautious about the edge of the field.