I was surprised how stiff salmon Alps is (in an Apple M0116 that was indistinguishable from new), while everyone else compares them with MX brown. I have a white Alps keyboard—in nice condition—that's so stiff I gave up with it. Alps switches are infamous for drastic changes in feel for, often, no visible reason. The problem with all the rare colours is that there are too few examples to reach a consensus on feel. I don't think we'll get a useful description of brown switches from a Korean — it's hard enough describing them in your own language. Of course, it hangs on whether I ever get a reply at all.
There is generally an agreement that white is stiffer than blue, but they're specified identically. Even having the specification doesn't provide assurance, although whole catalogues (which I don't have for blue+ivory, just a little photo or scan or something — it's extremely hard to communicate with alps.tw solely through Google Translate) would at least give you the known switches for a year and indicate which switches were sold concurrently.
For the Xerox keyboards, as I recall, you don't even have dates on the chips, am I correct?
Sandy doesn't like me doubting MouseFan's expertise ; ) But yes, I do consider it critical that as much information be reported as possible, so that other people can verify for themselves. I don't have any access to MouseFan though — he's a shadowy and mysterious figure.
This is the only list I've started to put together with regards keyboards, and I've tried to be detailed and provide references, although even what little is there already needs a lot of work:
http://deskthority.net/wiki/Keyboards_and_switches_by_yearIt's got a very, very long way to go before it's actually useful for anything, though!