Are there any features that you MUST have? As a quilter, I would look for needle up/down (and preferrably sideways as well), good lighting, feed dogs drop,.....
Compare the list to the machine features and see if one stands out. I had bought a Brother that had a really good Consumer Report rating and when I upgraded, I gave it to a friend. She uses it and loves it.
Can you go to a local dealer and see what they have in the line of used machines?