Like most things in life the answer to this debate is neither one way or the other. There are benefits and limitations to both items as learning tools. However, Warlock said something critical in his post, "I've trained ....". Warlock is an experienced RC heli pilot who has tought several people how to fly with the assistance of the co-pilot (Which beats a buddy cord where the instructor simply takes control and recovers the heli).

If you are forced to go it alone as I was, the co-pilot by itself won't prepare you for that first experience when you advance the collective and the skids come off the ground. The sim allows you to get comfortable with what the heli SHOULD do before you put your expensive model at risk. The co-pilot is like having an instructor there who can recover the heli to a level attitude when you lose orientation.

Jason