I have a Bernina 820 and the Juki F600, both have start/stop buttons and the knee lift. With the Bernina, I tend to use the foot pedal more, but will find myself using the start/stop button if I need to do something quick. The Juki is my traveling machine. In class, I do use the foot pedal, but when I was house and dogsitting (for a week) a while ago, the only place I can sew was on a kitchen island. It was too tall for sitting and using the foot pedal, so I used the start/stop button. I pieced a whole quilt top doing that and it was fine. I've never used the knee lift with either machines though.