It's very different from the technical pen I'm used to. Easier to make mistakes, harder to control, prone to big blobs of ink going everywhere, and the ink I use dries much more slowly which is a serious hand-smudging hazard.
That all said, I love that you can get different line qualities with the same tool. It makes what you're drawing much more expressive.
And there's also something appealing about the fact that a pen nib will never change or be out of stock or upgraded or updated. It's just a metal stick with a slot cut in it. It's cheap, and apart from slow changes in ink technology, essentially eternal.