If you teach someone to fly a 3 channel plane with the rudder servo on the right stick, when you move it to the left stick to put ailerons on he has to re learn to taxi, take off and couple the rudder with the left hand instead of the right. It is easier in my opinion to teach the person to fly a 4 ch plane using all the controls. I know there are lots that dissagree with this, but I have been teaching for over 25 years and have seen many people taught many ways, but prefer to teach on a 4 ch. I feel it makes a better pilot in the long run, but again, that is my opinion.

I do however leave it up to the student. Everyone has their own opinion and I have taught both ways.