Thanks to everyone! I ended up buying the Jazz. Could not test any of the other machines I was interested in and would not buy a machine I couldn't try first. I don't make bed sized quilts, so putting a "large" quilt through the Jazz won't be an issue. I bought at a local dealer who offers 100% trade-up for one year, prorated after that. My DH (who is an engineer) really put the machine through it's paces and he that it was a well-made machine.
Thanks everyone for their help.