Well, I received my GFT LX Bb in raw brass today from Ken Larson (
http://www.brasswerks.com ). When I opened it up, I looked at the workmanship. Everything is first class, impeccable fit and finish. So far, so good. I put my mouthpiece in and played a B major scale very softly and played some slurs. I tried some intervals and other scales, still playing softly. The horn is very responsive and resonant, the intonation is right on. The slotting is fairly tight, which I like. The tone is very complex. Rich in overtones and very resonant. Next, I started to put some more air into the horn. The tone stayed very rich and in tune. The upper register is very open and even. As a matter of fact, the horn blows very evenly, from low F# to as high as I can play (only about G6). The valves are very quick and smooth. Then I put alot more air through the horn, and the tone really lit up. It was easy to change the color of the tone, from warm and dark to sizzling.
I played a Lawler Model T before this, and while I liked the Lawler alot, I Love this GFT LX.