So, just did half a dozen practice lathers. The first few were face lathers, but the last few were palm lathers, as due to my face being a little irritated at the moment from some cream I'm using to get rid of a little bit of acne, it was getting a little upset from the punishment.
The virdict? I think it is a combination of bad technique and false expectations. In terms of expectations, I was expecting this brush to behave like a badger or boar brush. But it isn't a badger or boar brush, and as I'm becoming aware, it behaves very differently. It seems to retain almost no water, and so I have to constantly at water, little by little, until the desired consistency is achieved. With a boar brush, I just keep working the brush until it releases enough water to get it to where I want it.
Secondly, it doesn't seem to swell like an animal brush, which means it is not holding all of that newly created lather inside it. The difficulty I'm having is that the lather wants to reside either on my face (or hand) or around the outside of the brush near the handle, but not much in the bloom of the bristles... This may make it difficult for me to get 3 or 4 decent passes worth of lather, but again, I think this is probably just a technique thing that I need to get used to and adapt to. Maybe reload after 2 passes? I feel like it is precisely this property which people praise when they say they need to use very little soap to lather this thing. This makes sense, because a badger brush will 'waste' much soap as it creates heaps of lather inside the brush, rather than on your face... I guess I was used to that and used that lather up later, and so maybe I need to adjust technique. I suspect for bowl lathering none of this would be a problem, and this brush would be very very good.
Perhaps I would do better with a 23mm rather than 21mm... would that make much of a difference?
One thing I must say is that it developed lather very quickly. You add the soap, and some water, and this thing explodes with lather.
So, in summary, I will keep working at the brush, and will keep you posted.