Will the shop take her 750 for trade or consignment or would she keep it as a back up machine? I'd go with the 780. I got a great deal on an 830 Bernina that was a floor model with only a few hours on it. Very satisfied. This was my fifth Bernina. One did go to my daughter, but otherwise I have two at each home (summer and winter). I am very fortunate to be able to afford this luxury.