I use a mojo and as Stan observed, they work, but not all the time. It has to be in spot that they would land in anyway. In other words, it's a waste of time in a grassy field where they can't land and feed. As sold with the short stake, they are flat out hazardous because dove come in low and slow and you are at the mercy of low shooters of which my group is not. I have two sections of 6' anodized aluminum tubes that get it up 12' which helps a lot.
One dove field owner doesn't allow them. Stan's pivot irrigation tube gets it up plenty high.

One field I hunt, to be a little different, I carved these two decoys out of tupelo. One is a sleeper. I use them on a field that has a fake powerline running down the middle. I tie mono to the eyelet on the tail, and toss it over the line and it "hooks" on the line with the wire bracket. I tie it off to a stake. Only one is needed and it has been a magnet on this particular field. Some folks use them on live powerlines, but not me, Kemo Sabe.