I've just completed about 10 lathers with my custom D01 three band 22/46. I love my Simpsons brushes, but this brush absolutely kills the Duke, Classic, and Chubby in Best. Maybe there is variation in knots on both the Simpsons and D01 brushes, but I can't imagine a more dense brush than the D01 that I have. The knot (as stated earlier) is also significantly larger than spec (I measure 24/48mm). This brush in my view competes more with the Chubby's in super grade and represents very good value for money (Good backbone and a nice soft scrubby feel) One of the best brushes I have ever tried and about the only weakness I see is that it is a little hard for me to work with creams due to the density and fan shape.
Also it only took 7 days (excluding weekends) from the time I placed the order until I received the brush in Canada.