OK, I'll muddy the waters here. I may be showing my ignorance, and will gladly defer to the experts on here that have taken more turkeys than me, but in my very limited experience, decoys work better in the woods.
I don't want that "dumb" bird to have a long time to look over my decoy. Given enough time to look over the set-up he might realize that there is no movement. I want him to come over a rise, or round some brush and be surprised to see another "bird" right there on top of him. I want him to react to an invader or interloper without thinking. If he thinks about it, I've lost.
Again, limited experience on my part, but my hunting partner is pretty savvy and he's the one that taught me that.
What say you?