I've used a variety of shave brushes now: badger, boar, horse, and synthetic. For whipping up a good voluminous lather, I've had better results with my Omega boar and my Stirling synthetic brushes. I had poorer results with badger and horse, but the slickness—the true gauge of effectiveness, in my opinion—is what counts. I've gotten the same slickness of lather regardless of the bristle type, because ultimately it's the soap or cream that determines how slick the lather is. So what, then, is the point of debating the merits of bristle type? I think it comes down to which one prefers as it pertains to the feel of the bristles on the face. What are your thoughts?