I read some good reviews of the cashmere brush so I had to throw one in my cart along with the G5 series brushes I picked up, which I love.
I have to say, though, my favorite of all is the cashmere knot - it is very soft, has sufficient backbone (on the low side, but surprisingly effective), whips up an incredible soap, and retains water as well as any of my non-synthetic brushes do. This was a big (but happy!) surprise to me and I find my self reaching for my cashmere knot more than any other in my pretty extensive collection. Highly recommend!