This may be helpful.
http://www.evidently.org/2007/02/too-much-information/ It is written by a husband who wanted all the information before his wife bought. I bought a used Pfaff (love it) from a Baby Lock dealer. When I worked my way through the LONG article, I did agree with him on the importance of liking your dealership. That is also an important part of the purchase. Hoping this helps.