Seriously, neither! I have actually watched a crash due to a plane having a Copilot installed and then not set up properly prior to the planes first flight. Also I think the Copilot teaches you bad habits. It teaches you to simply let go of both sticks if something goes wrong and wait for the unit to try and keep the plane from crashing. Thats how the unit is activated! A good 4 channel trainer and a buddy box is all that is really needed. Trainer planes will flip upright from inverted and level themselves out if you let go of the sticks without needing any additional electronic gizmos so why bother?? I have taught 8 year olds how to fly with an LT40 as the trainer plane because it is so stable and mild acting on the controls.