Hello - I think some here have missed your question really. Of the 3 mentioned I've only seen one in person (Dufour's Simplicity at his shop) and of the three if I had the funds and the chance, it would be my choice. 
The RS price puzzles me too, since I agree that the escapement is not a major factor here, and certainly from what I see in photos the finishing would not take the same time that it does with a Dufour for instance. The photos I saw of the plates showed them to be mostly of a matte finished and not much anglage on the movement.
So I guess I agree that it's more marketing than the work that goes into it based on what I've observed.
Regards, Al