While those two machines are newer than the Pfaffs I have, my best guess is that the 6122 is probably the better machine of the two. I think it's one of the last ones made in Germany. Check for "Made in West Germany" on the column, probably inside the harp or maybe on the back. I believe all of the Hobbymatics are lesser end machines, usually if not always made in Japan, to offer a more economical line. Take fabric, thread, scissors and a machine needle with you and ask to test it. Run it through several of the different stitches to see how it works and if you like the feel of the machine. Generally, Pfaffs are very good machines and IMNSHO the older, the better. The 6122 might have IDT but I'm not sure without looking at one.