I don't like them. I think that they actually hurt pilots in their training. If a pilot knows that he can simply let go of the sticks and the plane will recover itself they will never learn the skills needed to do it themselves. I've seen this happen in pilots. It winds up giving them a false sense of security in skills that they don't have. Then when they try to move up to a second plane they find that they simply aren't ready to fly it because they don't have the skills needed recover it, and usually wind up crashing.

My vote is to stay away from them, you're better off learning to fly the plane yourself.

Ken