Pfaff is my favorite machine. In over 12 years I have never had any problems with my Pfaff 7570. Pfaff if very user friendly.
I have traveled with my machine and no problems with the Pfaff needing any adjustment when I got ready to sew.
Let your wife choose the machine she likes and fits her sewing needs. I machine is a major investment. She will love you forever, next her new machine.
Take care of this jewel of wife you have.