Fountain pen vs rollerball — what is the real difference?

A rollerball is a ballpoint running water-based ink: smoother than a biro, zero maintenance, one line width forever. A fountain pen feeds liquid ink through a nib: zero-pressure writing, refillable from thousands of bottled colors, line character that responds to your hand — and a cleaning ritual a few times a year.

The honest split: rollerball for pure convenience, fountain pen for anyone who enjoys the act of writing enough to notice the instrument. Many of us carry one of each and feel no contradiction.