Its not really "false economy" to start out with a 4 channel radio... compare the cost of the 4 ch system to the cost of a "flite pack" using the same servos... virtually the same price. By the time you need the 6 ch or higher radio... you probably will want to have 2 to 5 airplanes ready to fly at once, so you'd have been buying flite packs anyway. Also... the time between the original 4ch and the better radio allows the better radio price to drop, or they can come out with a better model. AND you'll have more of an idea what you want to look for in your better radio.

There's no down side to be found... except maybe a bit of delay in learning to deal with the features of the better radio (but they can just be something extra confuse you while learning to fly... so you are better off not having them at that time)