Out of the three Older Dishwashers that I've lived with, they were all about the same.
Dishlex Mark 8
Simpson Cascade
GE Potscrubber with Dual Spray arms.
They were all late 70's machines, did a good alround job on most loads. Couldnt shift burnt on stuff, but would clean most saucepans etc without a problem. Proper scraping was important, as there was no soft food disposal, everything got caught in the filter and needed cleaning. They all suffered from a lack of loading room, due to the space the upper spray arm took up, but were quick (When connected to Hot)
Out of that mix of oldies, the best I've used is the older 500 series Miele and my current 2000 series. Its a tall tub with huge amounts of interior room, flexible loading and the ability to blast off any burnt on food, even with the pin hole spray jets. The Miele wins hands down compared to the oldies.
The old ones seemed to be high volume at a lower pressure, where the Miele is low volue, high pressure and those needles seem to just blast the dirt off. The diffence is double the cycle time, but it can deal with soft food disposal.
Mum still has a Mark 8 Dishlex that does a good job, it just requires finess to shoe horn baking pans and the such in there.