I keep noticing the cult status of Double Duck razors. I'm sure they're great, but what makes them go for well over $200 on ebay? Do they have some magical properties that make them measurably better than any other razor new or vintage? Or are they top level razors that are just priced above all others because of scarcity?

The reason that I ask is because I have an Ern and a FWEngels special that I need to restore. I know that those are highly rated, but I've been curious to hear opinions as to how they stack up against a Double Duck.

Can anyone make good comparisons of those razors? Are they all in the same class?