ORIGINAL: JollyPopper
I still have a T6XA. It is a good, solid radio. Doesn't have the bells and whistles of the newer radios, but it works fine. As Carrellh touched on, it has a six model memory which means you can fly six different airplanes and the transmitter will remember the servo direction and trim settings of each airplane.
You can use the same TX for up to 6 aircraft but would either need to move the airborne stuff from plane to plane or buy additional "Flight Packs" consisting of servos, RX and battery/switch. some pieces can be dedicated to a given plane (servos and switch) and just move the RX & battery. Just remember that EVERY time you move the gear opens the opportunity for making an error. I recommend all new (used) flight packs.