NONE.... I have taught many folks to fly. It is like learning to ride a bike the first time. (you have to rewire your brain) You got to have someone to hold you up until you get the hang of it. It takes many weekends for the average joe. I taught a navy F4 fighter jock to solo in two weekends.
The best trainer is the Goldberg Eagle (40) or Eaglet (20) or the Sig trainer. They are very rugged and stable. ARFs are usually Lead Sleds which makes them too fast for beginners. Most ARFs have serious balance problems. Another good cheap plane is the Balsa USA Stick 40. Get the one with ailerons and convert it to a tri gear. Ugly plane but a fantastic rugged trainer.