When I learned to sew with sewing machines (around 1980) my school had machines with foot pedals and my mother's machine had a knee control. I vastly preferred the foot pedals. With my mother's machine, it was hard to get a slow start. Additionally, the knee control was a bit too high for me, so I had to have only my toes and the ball of my foot on the floor (raising the heel up as far as I could) to get my knee high enough. I know now that I should have created myself a foot rest with boxes or books, but I didn't know that then. I've never used a knee control machine other than my mother's.