I’m a big fan of fountain pens, and Pilot products are among my favorites. Their inks, which have terrific colors and flow incredibly well, usually sell in the $30+ range, are now on sale at Amazon for around $20. The Vermilion Red, which I use to grade papers, is marked down to $24.
I have several of Pilot’s Metropolitan Collection Fountain Pens, for every day use which, in spite of the under $20 price tag, write remarkably well. They’re on sale too at this point.
For me, the principal advantage over a ball point is that I don’t have to press down to write. When going through a hundred and eighty papers (my typical student load), pressing with a ball point can quickly cramp up the fingers. I have a large callus on the inside of the middle index finger from years of paper grading. If I’d started with fountain pens sooner, that wouldn’t have happened.
I love the fine tips, which inscribe incredibly thin lines that let me make comments on essays between lines of student writing.