I've been using this brush a decent amount of time in the past year. Since all the reviews on this site are counterproductive, I'm leaving mine as well.
The brush is relatively soft on the tips of the fibers, while providing appropriate backbone. However, it hogs lather like crazy. Every time you decide to make another pass, you are forced to use the soap again, or squeeze the knot, which ruins it. It is unusable with shaving soaps. If you force it on the soap for several minutes more, you might get something for a second pass. However, the amount of soap used and thrown away is enormous. It does get a bit betters with shaving creams.
I would not recommend this knot, or advise anyone to throw the money on it. In fact, there are many quite decent knots on this site, I've been using their synthetic one daily.