I've quilted on them all. Only thing I haven't done is hand quilting. I started on the Kenmore and couldn't make nice feathers on it, bought a Bernina & loved quilting small quilts on it and then sold the Bernina to help finance the Gammill Classic Longarm. I quilted professionally for several years, averaging about 4-6 quilts a month (I was working full time and a single parent of a teenager!). I got really tired of how big the longarm was and sold it. I bought a Nolting midarm machine and a Hinterberg Stretch frame and I found happiness.
I have written a much longer article on Squidoo about machine quilting - click here to read it.