My very first Amiga, an early 500 that I regretably no longer own, had the keyboard with C= key, and I loved the feel of it. Everything else feels "mushy" to me or, as in the case of an old, old PC keyboard I use, "clicky." The C= key keyboard is juuuuuust right. At some point, I ended up with an 2000 keyboard that was the same as my old 500 keyboard , C= key and all. I transplanted the guts into an 3000 keyboard casing I have (for the cool styling), got a PS2 adapter, and that's the keyboard I use now with my 4000.
If I ever again run across an early 500 with the C= key, I will buy it.