for futaba the inexpensive 6exa is a nice computer radio it has some advanced features and will take you through intermediate planes with basic mixes and will have 6 memory locations for storing different model settings. I prefer the 9c which is twice the price but it has greater flexibility with its computer mixing modes such as slaving dual elevator servos and allowing them to be trimmed together and greater flexibility for multiple rates and switch function selectability. Its better and more versatile then the 6 or 7c but its twice the money. You have asked a very difficult question where you will get 10,000 answers and every answer is right and every answer is wrong it depends on your true and intended needs. Try to buy a radio that is compatible with the radios of your instructors so they can buddy box you and that should be one of your first decision points. Go to your local club and see what the people there are using to fly the type of aircraft you intend to fly and ask them why they choose that radio. You should buy a cheap pos 4 channel radio originally to learn then research your future radio like luggage that you intend to keep forever. The cheap radios are just a few dollars more then a flight pack you would buy to add to a computer radio setup for multiple planes anyways. futaba 4 chanels are about 120 with servos and flight packs are worth 100 +11 for a channel crystal.