The stitching has probably been understated here. The 99s and 66s make a near-perfect stitch (see
http://www.sewalot.com/singer%2066.htm for more). Only machine Alex A Considers better is the 201.
Someone on this forum said the 401 is the best machine, but that might just be because it also has fancy quilting stitches built-in. I makes dresses, not quilts (yet - my daughter expressed interest in quilting yesterday so there's hope for me still).
Mike