What a great thread! I had to chuckle, as the first two boards tested here had some of the most traditionally maligned switches in the Keeb Kingdom:
Futaba MAs and
Mitsumi Miniatures.
I've been lucky enough to find one previously-unused board with each, and I think they're great! So I think those two designs may have simply not been as long-lasting as most mechanical switches, and didn't require as much use to lose their appeal.
Has anyone else been able to try any new or lightly-used examples, and been more impressed than they thought they would?