Doesn't seem to be mentioned in many mechanical keyboard articles these days, but I still find the buckling spring style switches an absolute joy to type on. The classic IBM Model M keyboard.
Note that even the Model M buckling spring mechanism is a step down from the earlier Model F buckling spring, which some people consider to be better. Personally I have not tried the latter as any surviving examples are quite expensive. But the mechboard world is a never ending hole, at least until you hit working beam springs, I think. :)
I had a model F AT, but sold it; it was a truly amazing keyboard, but the layout was a little too weird for me to get used to. Beautiful feel, though, and a satisfying wonky clonk sound.
My holy grail is a buckling spring ortholinear keyboard. I don'kt think that's going to happen anytime soon so I made a Kailh Pink XD75. It's as close as I can get, but that new Unicomp without the numpad looks amazing.
