One thing that wasn't mentioned, and you might find a good thing.

The 2.4 Futaba receiver has two antennas, but they're really short. I can't remember off the top of my head, but they're like 6 inches long. The antennas for the 72 MHz receiver is like 36" long. The longer antenna can prove difficult to route through the fuselage. Especially on smaller planes.

Also, the 2.4 Futaba transmitter has a shorter antenna that never needs raising. Also handy because if you read here long enough, you'll find stories of how people forget to raise the antenna on their transmitters.

I don't know about other brands/models of the 2.4 Tx and Rx though, so you'll have to find that out on your own.

As others have said.. Since your just starting out, buying into it now, there's no reason other than marginal money savings, to go with the older 72 MHz technology. And truth be told, a 6 channel radio isn't too much of a price jump over a 4 channel.

If I had to do it all over again, right now, I'd go with a 6 channel 2.4 Futaba. It gives me a bit more flexibility with 6 channels. A little more ease of use (insert antenna arguments here). A little more security at the airfield (no one to shoot you down). Etcetera.

Having said all that.. Here's a thought... Let's say you're looking around and all you can find is a 4 channel Futaba setup. I have one of these. It came with Transmitter, Receiver, Receiver battery, and 4 3004 servos. Nice little setup. It'll fly the Kadet wonderfully. Down the road, if you choose to get a 2.4. The servos are transferable. And the transmitter can always become a buddy box for training purposes. Worst case, you've waisted the money on the cost of the receiver. In the meantime, you've been flying. At that point in time, the Transmitter/Receiver setup doesn't owe you anything. Heck, you could probably donate them to the flying clubs raffle or something....