The size of the motor is important, but I think there are many other components that also need to be upgraded for power -- for example, the feed dogs. A machine such as a Bernina made in Switzerland will have very high quality parts -- with materials selected for strength and longevity as well as cost, and with parts tooled to much higher standards than most machines made in other countries.
This website explains EasyPeezy's experience. I honestly don't think it's about electronic vs mechanical. It's about over-engineering vs modern production decisions. Anyway, it makes for an interesting read.
http://vssmb.blogspot.com/2012/04/di...ndustrial.html