Has anyone ever used the CPD4 autopilot. I have read several reviews that say it works very
well, but would like to hear from someone who has used it on there airplane.

What do you want to use it for? As a way to train yourself, I would suggest that you would be better off joing an RC club where you can get proper training for free. For an experienced pilot, Autopilots can help tame a touchy airplane down while trying to land. For someone new to airplanes I don't suggest it. The unit has to be setup properly and some need to be calibrated before each flight. A new flyer probably would get it wrong resulting in the unit taking over and causing a crash. For a new flyer it can also teach some bad habits. The unit takes over when you let go of the sticks. So what is this teaching you? When something goes wrong, let go of the sticks and hope that the gizmo can sve your plane for you!!! < To me this is a terrible thing to be teaching!![8D]