When you get a 3 channel plane to learn on it adds another step to the learning process and can take longer to get the feel for the 4 channel plane as you tend to get used to the rudder for turning you find later that in actuality to turn a 4 channel plane in the air is more of a combination of alerions and elevator. Of course rudder can be used but in your beginner stages you will be taught alerions and elvators. Now after you have learned what a 3 channel plane flys it may as well be like learing all over again. IMO.