Ball points require a tremendous pressure, are not ergonomical and feel scratchy.
Rollerball are smoother and fountain pen ink rollers even smoother.
But fountain pens, I use very smooth medium and bold nib, glide.
They are beautifully made, one can choose between a light plastic/celluloid pen for a day of lecture writing to an heavier metal pen for card writing.
The array of ink available is dizzying and enthraling for somebody who loves color has much as I do.
The color of the pen can be use to match ink used with it.
There is such a variety of design, width, girth and weight in the fountain pen world that one is sure to find (at least) one favorite.
There is a vast price range from the $10 plastic stypen at Pendemonium to the million dollar one of a kind pen made of platinum and precious stone.
Then there is vintage and modern pens.
Vintages produced many years ago and passed on from loving user to loving user. Usually from generation to generation of the same family.
Vintage, found new in an old shop inventory and still in their original boxes.
Vintages used, abused and broken finding their way to pen shows part boxes.
Vintages half intact, half broken so lovingly repaired by master pen repairpersons that you could swear the pen is new. See richardspens.com
Then there is modern pen some custom made of urushi by master pen makers.
Some made of such beautifull and dazzling celluloid that one's want to grab them from the screen. Uh! don't do that your family will wonder why the computer screen is scratched.

Modern pen made of strong and beautiful plastics suitable for everyday use.
Modern made as series, so that you cannot help getting the whole collection like the Pelikan Cities serie.
In short, fountain pens are writing instruments of course but they are also objects of passion and fun and frustration when they need repair and above all pleasure.
And in this board they foster kind and loyal friendships.
What's not to love?