I have a Janome 6600 and love the knee lifter and going with out the pedal. With my previous machine (a small brother) only had a foot pedal and I ended up with a big knot in my calf muscle of my right leg from constantly pressing on the foot pedal. It was quite painful and would not go away for months. I had to stop going to the gym classes I enjoyed because each time I would put a bounce in my step, it would seize up and bring me to my knees.
The knee lifter takes a little getting used to, but is so worth the effort. I use it on my 6600, and my 10000 for embroidery. Once you get used to it, you do it without thinking.