I have two Pfaff machines and they both do a beautiful straight stitch whether piecing or going through four layers of Soft and Stable. Both have IDT. They also have five rows of feed dogs. I never have to pull fabric through. My previous machine was a Huskystar by Viking and I had trouble going through thick fabric with it. My 1965 Singer would also go through anything. It died about 10 years ago. I do wish I had kept it.