i agree with most that 3 channels is not so different from 4 channels if you're already in the flying instead of learning phase. if you can fly a 4-channel plane, you can fly a 3-channel plane but not necessarily the other way around. if you are not on a budget, getting the 3-channel can be a great way to enjoy flying and possibly sharing the experience with a friend. a 3-channel is a lot more stable and releasing the sticks will get you reoriented much easier. on the other hand, if you want to continue with 4-channels, and you can't afford two planes, i would suggest a new trainer or, if you're a good builder, adding another channel to the 3-channel kadet.

i personally love 3-channels for the nostalgia of the hobby. the way the tail wags and the coupled rolls are fun to watch and flying inverted always gets my stomach in a bind. but if i were you, learning to fly, i'd go for one of the recommended trainers. my two cents.