Since my BK8 is one of my favorite brushes, I had to try the BK8S. It is a very fine synthetic brush. My only complaint -- which is a small once since I use the BK8S a lot and like it -- is that it is not entirely a replacement for the BK8 since it is a bit smaller than the BK8, probably more like a BK6. As I said, though, it is really excellent synthetic brush that's solidly in my rotation.