I've owned a 503A Slant-O-Matic Special since 1964. I absolutely love this machine. I do piecing on this machine and have added many cams in the last year; but honestly have not tried any of them. It was a cheap purchase on Ebay. The only thing that had to be addressed over the several years of ownership is the bobbin winder tire rotted away and I purchased a replacement. The replacement was slightly larger so I had to make an adjustment. The other thing was the stop motion wheel would not disengage the needle bar so after several years of "I've gotta fix this" my DH got the two wheels apart and I fixed it.