RE: O.S. 70 4-stroke & U-Can-Do 40..
Four Strokes are great!
They sound cool (more scale sounding)
They can swing bigger props especially at lower RPMs which is very desireable for 3D.
Very high torque motors.
More efficient fuel wise and cleaner running.
The most important thing is the superior torque, especially at lower RPM. Two strokes need to be wound up to generate their power.
Riff