You can not beat the vintage machines, thats why they are the only ones I own.
My newest (and prettiest) machine is a Kenmore and its just 46 years old and my only electric machine.
After that the newest (and my favorite go to machine) would be my 1948 Universal 15 (61 years old). But I own and use several machines on a regular basis that are well over 100 years old.
Billy