I haven't really programmed in Lisp or Dylan, but the code I read certainly seemed the better because of the punctuation in function names. It gets denser, but stays readable. A question mark signals 'returns boolean' just as strong as a "Is" or "Has" prefix, and there AFAIK is nothing in other languages that signals "modifies its arguments" as strong as a ! suffix.

I also find that Dylan's convention of using brackets in class names rapidly grows on you. But maybe that requires working in Forth as a warming up.

And of course, hyphens not only look better than underscores, they are easier to type, too :-)