I installed my SawQuiet5000 yesterday and have the same issues you did SafeAirOne. On the slow speeds it needs help to start some times. I could live with that but when I sew at the low speed, it will click along for 20 stitches and then jump about 5 stitches. Also, if I am sewing at a low speed, when I let up on the treadle, it will surge 5 or 6 stitches. So far this is not good at all. Have you heard anymore about your unit?
This is a national holiday in Canada and they are closed. I will have to call them tomorrow.