I'm not saying Topres are bad at all... I'm just saying that until I try a Topre the only association I have with "cupped rubber" is a rubber dome keyboard.
Believe me, I'm sure I'll end up owning a Topre someday in the near future...
What is your experience with rubber domes? Even cheap ones vary hugely from model to model, brand to brand.
A lot of them are very spongy – Topre domes have very clear, pronounced tactility with no sponginess. Old "midnight grey" Dell keyboards for example are highly tactile but the tactile point is very sharp like ALPS, and they're very stiff and balky – normal Topre keyboards are variable weight at only 45 cN for the centre keys, vs anything up to 60–65 cN for a normal board, so they're easy to press and soft and smooth.
And I mean
smooth. Much smoother than buckling spring. There's no scraping, and no flex, creak, or rattle. The switches have sliders, where cheap rubber dome boards just have a shaft for the keycap, which can lead to binding (the key jams part-way down because it's not sliding vertically). The keyboard itself is suitably heavy, so it doesn't slide around the desk.
The capacitive switching means that it's truly NKRO (USB limitations notwithstanding) as it's completely immune to ghosting. Don't know if it does PS/2, never cared.
Plus it's really quiet – quiet even by full travel dome standards because you don't get all the horrid rattling and shaking that you get from, say, a cheap Dell.
Topre is a formulated approach to rubber dome that guarantees quality year after year. I didn't believe it until I bought one either – I didn't realise that you could get rubber domes so right. There
are nice domes, such as the Dell KB-1421: it feels almost as good as Topre, but it's still undeniably cheap, and the KB-1421 is the only dome keyboard I've used that comes anywhere close in my experience. Most of them are just awful.
Is Topre better than Cherry MX? Depends. Topre doesn't click. Topre doesn't do linear. You have fewer options for available force curves. The problem with Cherry for many is that they can't get the balance right on force curves: red, brown and blue are too light, clear is kinda weird (but IMO so much better than brown), and black is too stiff. Topre is the perfect weight that Cherry just can't pull off, not unless/until they formally introduce ergo clears anyway :-)
It's all personal preference, but I cannot deny that Topre do rubber dome right, and it's probably the best tactile switch on the market.