I used a model M a few times back it the day( at a family members house), the first keyboard i owned was on an acorn A3010 i think it was rubber dome but it was a good rubber dome.
Unfortunately it was then a chain of crappy keyboards (apart form one cherry rubber dome that was quite good) until i got my black widdow, things have just been getting better and better since then.
EDIT
the acorn was good as it had a plate! and not like current rubber domes that use the thin and cheap case so they bend and flex like a gymnast.
http://acorn.chriswhy.co.uk/Pics/A30102E.jpgEDIT 2
Check out that layout i had forgotten that! Ctrl where it should be !!!
EDIT 3
Looks like it is not a dome after all
http://www.classicacorn.freeuk.com/32bi ... base3.htmlthat's a spring over a membrane ( capasative ?) i see no rubber in site, any of you vintage boys know what the hell is going on there e?