One guy I know has consistent success with a buck decoy. He puts it on the edge of a food plot they have in the woods. He doesn't mess with it until November. He is looking for a big mature buck or nothing. And that's what you'll get. I think it scares off young bucks and doe. He lives on his hunting land and owns his own business so he can be very selective and be out there whenever conditions are right.
My one buddy tried a decoy a couple times on one of our fields. Every deer came out, looked at it, stomped, snorted and never came near it....or him.