Do you 51 lovers have any preference between American and British versions? What about the early aeros vs. the Mark IIIs?
I like both the U.S. and British versions. In my experience (and this is totally subjective), the British nibs seem to be a bit "softer" writing than the U.S. nibs. I prefer the earlier aerometrics (1949- early 1960s) to the later ones. They just seem to me to be more solidly built.