Japanese Pencil Comparison: Mitsubishi and Tombow

I recently purchased several of the more popular Japanese wood-cased pencils from Jet Pens. I got the Tombow 2558 ($1 each) and three Misubishis: the 9800 ($0.70 each), the Hi-Uni ($2.35 each) and the 9850 ($1 each). All of the pencils are the standard HB/#2 hardness. As far as I can tell, the only difference…