Out of curiosity, I've been watching a few restorations of those spectrums, and I've noticed the keyboards having a rather peculiar construction, judging by today's standards. They have 2 springs, the small one, as far as I understand, presses the membrane layers together, and the larger one returns the key into neutral position once the key is released.
I personally haven't used any spectrums, yet I've encountered the very same construction on a keyboard of a Russian clone of said machines (namely, zx atas), and to this day I haven't touched anything worse... The only way I can describe it is like trying to type on a piece of raw meat.
So, if anyone here had a chance to type on the original spectrums, was it this bad? I suspect otherwise since I haven't heard of crowds of people requesting PTSD treatment, but the whole thing still somewhat bothers me 😅
I had a +3. At the time it was much better than rubber 48K keys.
If you are expecting cherry mx switches, you will be disappointed.