I've been using the rotring 800 mechanical pencil for a while now ... until it randomly broke down (no, I did not treat I strangely in every way or form). I'm using the - much cheaper - Kuru Toga Advance now ... which rotates the graphite slighly whenever I lift the pencil from the paper, leading to a sharper tip and thus a sharper script.

Plus, I am a lot less concerned with losing a 5 dollar pencil as compared to a 50 dollar pencil.