If you learn on 3, you have to re-learn everything on 4.
Flyboy,
Maybe you could explain this statement since the it is written it is wrong.
If you set up your plane to fly 3 channels then you plug the rudder servo into the airleron jack in the Rx Aside from rudder turns making the model appear to "skid" around a turn there is little or no difference. Learning on a three channel plane Does not require one to relean everything