I heard that the razor rock are pretty damn good.I have had great success with AP Shave Co knots.
Also, the Razorock BC Silvertip synthetic.
I have the white one with a nice wooden handle and it really is like spring steel, but I've found if I let it soak in hot water the fibres soften and become more compliant. It may be because its the first gen of the hi brush, but in Omegas' defence I really like the S brush. IMHO as near as it gets to a boar synthetic, whether by design or accident, dirt cheap and absolutely great on my old mug.Which Hi-Brush would that be? There are two different types. Black hi-Brush - harder, meant to emulate pure badger, and white hi-brush, softer, meant to emulate the higher grade badgers.