Neither, haha. I write on loose-leaf. I just don't really like notebooks because I can't rearrange sections, and looseleaf gives me more flexibility. I keep all my looseleaf stuff in one of
these so it doesn't get lost. It's also great to press on.
I'm actually faster at getting my ideas down on paper than on a computer because my typing speed sucks, and if I do carry around a notebook with me, I quickly jot down any ideas I have. And I don't need to worry too much about other people reading it--it's actual work for me to make my handwriting readable to anyone apart from me.
But yeah. I write on looseleaf, with a .5 mechanical pencil. I'm rather particular about that.