The grip on the pen can (should) be much lighter, and the movement on the paper is smoother, so it's easier to write in a cursive script, and more comfortable to write a lot.
It's amusing to see discussions on fountain pens online. They're held in high regard by a section of HN, with discussions around ink type, importing Japanese nibs, using special paper and so on.
Mine cost €13 from a shop in Germany. It's a typical pen a high school student might own.
(You can buy them for as little as €4, although those are more likely to leak if dropped etc. Typical for a primary school student though.)
