Of all of my horns, the Lightweight 400 is the most challenging to play. You really need to be paying attention to hit the notes right on and be precise in your articulations.
On the other hand, the Custom Built is the easiest to play. It almost plays itself.
I usually play the Lightweight 400 because I think that it forces me to be a better, more precise player, and let's face it, the other horns weigh a lot more!
Is this philosophy sound or delusional? Other people have noticed that my playing has improved, but that might have happened anyways using easier-to-play horns.
I almost have this ravenous beast tamed. The Curry 3M helps a lot!