What is it like? Of course the first thing that stands out is the weight, especially the slide. It is so much easier to move the slide, which makes playing faster passages more possible and even fun. Sixth and seventh positions are more accurate and accessible also because at length, the slide doesn’t drag like a brass (or nickel) one does.
Another bonus is that my left shoulder is finally recovering from a bout of chronic pain most likely caused from holding a much heavier instrument for too long and not taking enough rests. In short, I can practice longer with less fatigue.
The rotary valve is open and fast and I find the trigger register to be much more accessible and useable compared to a large bore Minick and a Rath R3F.
And then the burning question: does it sound like a real trombone?

What I find to be a more interesting question is: what is the sound of greater ease? After so many years of playing trombone, I know and love the sound of brass and its variations. The cf material however, opens up new possibilities for expression through ease and subtlety and that is more important for me now than if it sounds like a real trombone. Plus, my music teacher colleagues haven’t said anything about the sound compared to when I was playing my Rath. The trigger register is better, the high range easier, the slide is lighter and I can project and play louder when needed. What’s not to like? Am I saying that cf is better? No, it’s just different in a valuable and interesting way.
At this time in my life and what I’m doing musically, the Butler is just right. In fact, I hope to get my hands on a small bore version as well. These observations and opinions are only mine and applicable to me in my current stage in life. I have no business connections with Butler. Your mileage will vary!