Sewing machine preference is pretty subjective. Personally, I'm a Bernina girl. I love my Berninas. That said, many people don't care for them at all. You will probably have to just try a lot of machines out and see which one you like the best. One thing I will say is that IMO Quilt Festival isn't the best place to be trying out a machine. There is a lot of confusion and hustle which, for me, would make it hard to concentrate and decide. I prefer to go to a store where I can quietly try out the machines that I'm interested in.
Whatever you do, decide before hand which features you really want, which don't matter and which ones you just have to have. It will help you narrow down the choices and not get upsold a lot of machine that you don't really want/need.