I had many preconceived notions about horn mouthpieces, including their being brittle, uncomfortable, hard, and that they mostly all had the old orific style button and no slot to speak of. I took a gamble on a Ropp Vintage Stout bulldog and have since been proven wrong on most of those assumptions.
The material is comfortable to clench, with similar percived hardness to high quality Ebonite, yet it doesn’t oxidize. While the Ropp’s mouthpiece is relatively thick at the button, that’s largely due to the shape dictated by the style of the pipe. I have since acquired horn-stemmed pipes by Peter Heeschen and Chris Askwith, both of which are thin and comfortable and wih modern drilling, slots, and buttons. The horn wasn’t a problem for them. Finally, I have a very old GBD lovat with a horn stem and bone screw-in tenon. It is in absolutely perfect condition and is probably 100+ years old.
The Heeschen was an estate and has a tiny triangular cavity in the upper surface next to the button which is believed to be from a sharp tooth, so it’s soft enough to damage. That particular pipe has a signature Heeschen saddle bit, so it is very, very thin and supremely comfortable.
So, horn isn’t perfect, but it’s become something I like in a pipe. Comfortable and handsome, yet practical.
BTW, the Ropp is an absolutely terrific smoker and extremely lightweight.