RE: 3ch going to 4ch
Iwould agree with all said above about flying site size. Another good 4 channel to look at is the Parkzone t-28 (not micro). It is a cross between a trainer and sport type of plane.
You can take landing gear off and easily hand launch. It flies slow and stable if you want or fast and aerobatic. It is a great all around plane. You could also look at the Parkzone Wildcat whiich is a little smaller in size than t-28.
I was worried about going to 4 channel, but it isIMHO easier than just the 3 channels. I also woudl put the ailerons on the right stick where you had the rudder (use a mode 2 transmitter).
Hope this helps.