Love my Wee Beast. Great for face lathering creams while sporting facial hair. Omega Wide Waist Mighty Midget is another to check out if you like smaller brushes.
I had one for a brief period years ago. It was just too small for me to use comfortably. The smallest brush I was able to get along with was the Omega 11047 as the handle was just slightly larger.
I own one. Bought it from a member here, not @PanChango . As a work of the brushmaker's art, I think they are amazing, and they perform better than you would expect for the size. It's a very small brush though, and at the end of the day, you will find very very few people using one as a daily driver, and very few who keep it in their rotation. It's not the size of the knot, but the handle that is the issue. If you want a small Simpson brush for travel, I recommend going with the Case (aka Wee Scot 3) for a more comfortable brush to use.