An interesting discussion whose conclusion is: "What you choose to write with for your own personal use and pleasure is a decision that you and you alone must make and you and you alone can make. There's no right or wrong here, or best or worse, just you personal feeling for a device that suits your needs and satisfies your desires."
I would agree, though I mostly use mechanical pencils these days, since they are best for underlining and making marginal notes in books. What I used to do with pens, I now usually do with some sort of keyboard.
But don't just read the post for the conclusion.
No further comment!