I like my Janome 6500. Very similar to the 6600 with one or two features missing... start and stop button so you can sew without the foot pedal and ofcourse the 6500 doesn't have the Accufeed system.
6500 new in these parts cost 1800.00 three years ago. They have a new top of the line machine coming out in May so there will probably be a big dip in prices on both the 6500 and 6600.
Will she let you turn on the machine and sew with it before you buy it?