Sharon,
As nice of a machine as it is, unless I could test run it and test sew with it, I'd pass. It would make a good piecing machine, but it has one problem that I can't tolerate. The position of the light in relationship to the presser bar lever. I have a thread running here on how I changed out the light on my HOTHER due to getting burned. That 15-91 is set up exactly the same as my HOTHER.
Like notsureif said they are a PITA to use.
Honestly I'd love to have the cabinet, but I'd put a 66-16 in it. Bigger harp, better placement of the tension, regular belt type motor that's easy to replace and work on.
JMHO
Joe