Ergonomic: I got the smaller size because my Shavemac is such a cream hog. The brush is small but is not too small. Although in hindsight I think I would have prefered a size 12. But I am happy with this one.
I have a Plisson Classic Black Acrylic Handle in Pure Black Badger, size 12, on order from Atkinson's. After reading this thread, and your review, I am so excited! The wait is killing me, but it "builds character".