Definitely the eternal debate. We have been using two Mojos, four Wonder Ducks, and a Wake Maker decoy system in our hole. It has been working incredibly well. The Wake Maker works like a jerk string, but the movement is continuous. I think the key to motion decoys, Robos - Mojos - Wonder Ducks - or whatever else, is to have several of them. Reason I say this is because if you look at real ducks in a pond, all are moving, not just one flapping his wings wildly. So the more you have the better. If you are only gong to use one, just don't use any at all. We got around the enormous cost of all this by each guy pitching in his own Mojo or Wonder Duck. Check out this Wake Maker though, it has really been good.

http://www.wakemakerducks.com/