I seldom use it but I do a couple of times during the season and usually only during the rut. I'm still waiting on the "all out attack" on my deke by another buck though. I have drawn them in within a few feet of my deke and a few times even nose to nose. I always set up mine as a buck. I've never had any luck using it as a doe. What I've seen more often than not is that at the very least you have a chance at stopping a buck long enough to give you a shot if needed. Also in most cases it seems to spook does.
I generally set mine up facing me at a 45 degree angle to my position. Reason being is that a buck will tend to approach another buck head on rather than from the rear. Often he'll be so concentrated on the deke that he won't pay much attention to you or any slight movements you might make. This also "swings" him around the decoy possibly giving you a broadside shot.
Ironically, the 3 D targets (all set up as bucks) I have positioned in my backyard regularly get attacked, especially pre-rut into the rut. A couple have been torn up so bad I've had to replace them.