I only have problems with electric sewing machines; they're simply too fast for me, no matter what, and I can never sew in a straight line with them (although you know my general problem with straight lines already). Grandma's old, mechanical one worked like a charm for me because when the task was delicate, I could turn its wheel by hand, as slow as I wanted. Alas, it was too big to be used in this tiny flat, so we had to give it away. A shame, really. :(