Yeah, they are "rubber dome", which scares people away. (They have a rubber dome, but they also have a spring. And they are capacitive; you don't press the key all the way down to type the key.) They are like Cherry browns done right, tactile, quiet, and no requirement to "bottom out". Topre really goes over the top with the part of the key that presses the dome; hard ABS plastic, with anti-rotation tabs, and a shape that makes even off-center hits go straight down. (You can push the key from the side, instead of from above, and the key doesn't jam; it just slides down normally. It's really brilliant.)

Oh, and this is true of both the Realforce and the HHKB Professional; same switches, different layout.

I am intrigued by what you say, but I wonder how easy the Topre is to keep clean.

Of all the things in an ordinary office or home (including toilet seats and such) phone handsets and computer keyboards tend to have the most germs. One anti-germ measure I use is to replace my keyboard every year or so, but replacing the Topre every year is more than I want to spend. Replacing just the keycaps would control germs just as well as replacing the board, but where would I buy keycaps for a Topre?