"And I love the way the bobbin fills. No taking it out or unthreading the machine! I wish the new computerized Brother I have worked the same way. "
That's one thing I really liked about mine. My frustration was getting the tension right. The OSMG I took the 758 to, improved it a lot. He adjusted the bobbin, which the manual says cannot be adjusted. Also, there was too much pressure on the presser foot. It really helped. It didn't help enough that I wanted to piece another quilt on it, but it works just fine for the 5th graders.
Of course, that could be only a problem with the ones with the rubber feed dogs. Both the 758 and the 778 have the rubber feed dogs. I wondered several times about replacing them with other kinds of feed dogs.