Merkur Progress 500/570 - differences?

Amazing! Looks like it might lack 'weight' though.
The German text in the linked post reads something like:
Although this razor is made from Pollopas, it's nevertheless quite heavy. Heavier than some all metal razors.
The guy also says that it shaves just as a normal Progress does.
Pollopas was a brand name for a type of urea-formaldehyde
 
Back then in 1956 the gold plated 572 with leather case was 28 German Marks,
the chrome plated 500 with pastic box was 9 German Marks
and the cool Pollopas 830 could be had for a mere 3 German Marks in a cardboard box...
Good luck finding one though...