You can't go wrong with the 6500 in my opinion. I sold mine and bought the 6600 specifically because of the built in walking foot. It was a real pain! Free motion quilting was a pain because the quilt did catch on the dual foot mechanism. Changing the dual feet was awful. So I sold the 6600 and bought another 6500 and have been extremely happy with it! This is a real work horse and I think it will go down in history similar to the Singer Featherweight! But everyone has their own opinion and I think it would be great if you could spend some time with each machine before making your selection. Good luck!