I have a Pfaff Tiptronic 2040 with IDT and love it. I used to have an earlier Pfaff Tiptronic, but a friend took it when I bought my Babylock Serenade (which also has upper feed dogs). I wanted the knee lift for the presser foot (both hands free, yay!) and thread cutter of the Serenade, so now my Pfaff Tiptronic is my backup machine. You can't beat having upper and lower feed dogs. I don't ever plan to sew with only lower feed dogs again, if I can help it. Not all Pfaff machines have upper feed dogs---some of the really early machines don't have them, and I don't think the "Hobby" has them, so be aware of that when shopping for a used machine.