I would half to say it is stick movement to servo travel (and speed of servo) vs. personal preference for what the plane is doing with the amount of stick input applied. I know when I went digital on my nitro on road cars.... it was a day/night difference. I use expo to get my "linear" feel to what the car should be doing with the amount of input I am putting in on the sticks. Some of these digitals are very fast and a 1/8" movement on the stick is a true 1/8" on the servo.