I've been writing with Mitsubishi ball pens before but switched to a fountain pen - a simple Lamy with a fine feather - and I can really recommend it. The writing experience is very nice as the pen requires very little pressure to write and with a little practice the result looks very good. I also bought a small flask of black ink and an ink converter (a small ink cartridge allowing you to draw ink from the flask into the cartridge via the pen) to refill it, which I have to do roughly every two weeks. I've been almost exclusively writing with the pen since more than a year and went through less than a quarter of the flask so far, so it's more economic than using ball pens as well I'd say.