Nope, have not yet ridden the Hinge. I see your point on the last photos, but also see the seat post/handlebar stems are at different angles. Does that make a difference? I do not know, but what about the attached photos? Dahon, bent over riding position, just like mine. Hinge, straight up and down.
Also, the Hinge stem is adjustable, the Dahon is not.
What am I missing?
Tom