what's your impressions on switch (capacitive BS versus blue ALPs) and chasis (IBM F vs. early model M vs Omnikey) differences?
Of course these existential questions are of the type: Which is a better vehicle, a sports car or a pickup truck?
First, to be very picky and technical, let me reiterate that I do not believe that it is possible to hear or feel any difference between the "switch types" of IBM buckling springs - the activation of the electrical impulse happens underneath the "catastrophic" buckling of a spring which obliterates all other sounds and feelings - and that all of the perceived differences of between Model M and Model F are in the "chassis" which I would define as the entire frame system (including various internal plates as well as the outer case itself). I do, of course, believe that the capacitive switching system of the Model F is vastly superior in terms of durability, etc, but I don't think that humans can feel it.
That said, thousands of words have been expended here on M vs F so I won't beat that dead horse any further than to say that the multiple metal plates (2 of them in an interesting tension/compression relationship) in the Model F make it resonate ("sing") with a quality that I can only call "life" while the plastic barrel plate of the Model M makes any resonance it produces dull and lifeless in comparison. So, while the floss mod quiets (ie reduces the higher resonances and "ping") the buckling springs without "deadening" them, the M had little "life" to lose in the first place.
The Omnikey, like the Model F XT and F-122, has a metal case back. This case back is at least as thick as the Model F, and has a magnificent beige paint job that is probably very thick and baked on. This solid heavy back contributes to a very solid feel and sound. The case upper is very well made, but they do tend to yellow if you are unlucky. I do not care for the removable (and do not be tricked into imagining that a common male-male PS/2 cable can replace it) AT-type cable. I am going to fabricate some other cable options but that is for later. Suffice to say that the Northgate case, second only to old IBM cases, is the best I have ever had. But, I still drool over aluminum cases!
So, about those blue Alps switches. Naturally, there is a desire to compare them to all the other "clicky" switch types. In general, Alps activate high up, so that you have to give them a sharp snap at the top to get them moving, but then they seem to "fall away" afterwards. I consider this to be ideal for typing, since there is ample time to get off the key and bottoming out is rarely an issue. This, I believe, is why Alps are the best switches for typing, by far. And I like the clicky ones best, of course, but the orange ones are good.
What are the differences between blue Alps and white Alps, since there seems to be at least one set of specs that say they are the same?
Honestly, I think that the only substantial difference is weight (aka force) but the lighter blues seem somehow "crisper" because of their lighter touch. My experience with old-style complicated white Alps (on at least 3 different models and manufacturers of keyboards) is that whites are a relatively heavy switch, but that blues are considerably lighter. Other people have other opinions.
I gave these a quick light brush with Krytox, which is probably a good idea for almost any switch.
All in all, the upgrade to blue Alps is subtle but real, and valuable. However, for someone lacking in soldering skills, time, money, or motivation, buying an Omnikey 101 with white Alps and cleaning and lubing them is probably an excellent plan.