For piecing, I think it's hard to beat a Pfaff because of the built-in walking foot. For me, I love my Bernina 1230. It's hard to go wrong with either of those brands.
My sister has a later model Pfaff (maybe 5 years old) and it is more "plasticky" than my metal Bernina, I don't like the curve in the base (that holds the attachments), and I don't like the placement of the foot lifter (different from other machines). However, if I weren't used to my Bernina I would *love* sewing on that machine! It has an incredible decorative stitch selection and sews and quilts beautifully.