ORIGINAL: quicksand
Does the 6 channel have end point servo ajustments if not get the 4 channel to start with if money is an issue! $130.00 with servos and receiver combo great for a trainer and then you can move all that gear into a Balsa USA Stingray 40 or a Sig 4 star 40 for the second plane. The next step would be to buy the 9C and get a OMP edge 540 profile to add expo. on the control surfaces to learn and refine your flying ability and will make you a great all around flyer in a short time frame.
The 6EXA is a great beginner radio. It has model memory for 6 planes, allows end point adjustment, exponential control and mixing functions. It's relatively low priced (about $180 complete at Tower) and should do everthing a beginner needs for their first few planes.
Some of the posts here make it sound like upgrading later will require tearing all the radio gear out of your first planes. Not so! My EXA will always fly my trainer, and my Bipe and my extra300. If I decide to go to more complicated aircraft later, that will be the time to think about a more capable radio. Just my opinion.