I have been impressed with the AP Shave Co synthetic brush guide, but I wonder how many of the well-known inexpensive synthetic brushes compare to these. My synthetic brush experience is with the RazoRock Plissoft & Mühle STF. I agree with the brush guide that the STF is very soft but without any scrub. Is there an unofficial guide or comparison review of the qualities of the most common synthetic brushes on the market? Are many/some of the synthetic knots the same but with different names?