FM (PPM) gets a little too exciting for me, if the radio sees some interference. The servos go every which way. It's kind of hard to jump out of the path of the plane because you don't know where it's going. With PCM there's less excitement. With interference, the radio can be programmed so that the engine goes to idle and the rest of the servos go to neutral. The plane may crash, but it's in a straight line at relatively low speed. Think about this scenario: your plane with PPM coming in for a landing, wheels touch down and roll out, you turn the plane to taxi back towards you, someone turns on your channel, plane goes full throttle and headed in the direction of the pits.