The oldies are generally all metal construction as opposed to plastic. They were much simpler and you could service them yourself, all they needed basically was a good cleaning and frequent oiling and you were good to go. The new ones have a lot of electronics which you can't check out yourself. They are subject to ruin by magnets. The parts are plastic and they break. They are easy to get out of time. Now don't get me wrong, I have several electronic machines but these are the basic differences that I am aware of. I also own Featherweights and other old machines.