That depends on the nib and ink. I use a KaWeCo pocket fountain pen with an extra fine nib, and Montblanc ink, and it writes as well or better than the nicest Japanese ball pens I have tried.

I also like the pocket-pen format. I seldom lose a pen since it lives with my keys and wallet. That pen, plus a thin crosshatch notebook I keep in my back pocket means I can take notes much faster than on my smartphone. Then I photograph my notes. Google Lens is getting scary-good at recognizing my idiosyncratic writing.