Last week, amongst the assortment of high-grade pencils I selected at the Wonderpens store, I threw in a couple of 8900s in 2B and HB. For 85 cents, why not?
Simply put: my next purchase will be a box of the 2Bs. The lead is smooooth and leaves a rich line, if desired. The wood is easy to cut away to leave a long lead exposed for drawing. I'm impressed.
It's less than a third of the price of a Mono 100, but the 8900 is far more than a third of the quality.
As an aside, I do find that the Tombow grading is conservative. I would rate their 2B as equivalent to Faber Castell's 4B, to my eye anyhow.