I use rapidographs sometimes, and Copic Multiliners, but also dip pens.
What the dip pens lose in portability they make up for in easy cleaning and choices of ink. And expressiveness, I think.
I inherited a lot of nibs from my wife's grandfather and have tried most of them (there are hundreds)
The one that stands out for me lately is an Esterbrook 6 Textwriter.
According to Wikipedia Carl Barks (a Disney artist) loved the Esterbrook 356.
I have some 356s and they are good, too.
I also like the Gillott 1066