I'm thinking about snagging one of the Topres that EK has on sale and if I'm doing it I need to act fast (i.e. today) while I still have family traveling in the US (significant savings for me).
I don't consider myself "special needs" but one thing that really bothers me about some rubber dome keyboards I've used in the past, particularly some particular runs of MS Naturals, is when keys stick when not hit at perfect right angles. Any side force could jam the key or snag it briefly when being pressed. Also, some keyboards have more key cap wobble than others in these situations and lead to instability. I notice on my temporary Logitech Illuminated that sometimes the keys go a little wonky and feel odd under my fingertips. Sometimes this is a gaming issue (rapid, panicked, unpredictable stabbing at keys), sometimes a typing issue (I've had shift keys hitch, sometimes other keys farther from home row).
I see mechanicals as a general way to avoid this. There's a discrete switch with a stem, and not a plastic plunger in a plastic tube sliding up and down. The side view of a Topre switch (seen at EK) seems to show similar tube-in-tube construction. I haven't had a hint of this issue on my model M despite it not being mechanical switch based, however, which is one of the things that makes it feel great.
Thanks,