Several people have asked about Ducky's "green Alps" switches. I purchased a bag of each of the two Ducky types to compare with my stock samples from Xiang Min.
The black linear switches (KSB-N) appear to be no different from the stock product.
The green clicky switches (KSB-C) however have a much more tightly-coiled spring:
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Green is Ducky's custom switch, and ivory is a stock switch direct from Xiang Min.
The end result is that Ducky's green Alps switches feel roughly the same as a white Alps switch, but a touch balky — my complicated white Alps switch has a smoother tactile peak. (Though my experiences with using white Alps keyboards have been largely negative.)