They run quieter and smoother than their zigzag counterparts. From what I've seen only the high end modern machines compare.
They were made in a time when quality mattered and people could tell the difference. They were designed to last, not to break and be thrown out as soon as the warranty ended. Planned obsolescence hadn't been invented yet.
Rodney
EDITED TO ADD:
They were also built in a time when beauty mattered. The designers didn't have to design the cast iron stands with all the fancy scrollwork. They did it because they wanted to and because they could. The people of the time also would have rejected anything that wasn't both functional and beautiful.
Compare the craftsmanship and art of an old black machine to a modern plastic one with a sticker added to it.
We have lost a lot in our pursuit of "progress".
Last edited by Rodney; 01-12-2015 at 07:45 AM.