Interesting Q; as i just have a new set in D sent from Binci, and i tend to agree with Bryan, very responsive, and also a great sound. Had a C accordion in a while back with brass, seemed a little oxidized, but did not notice any thing exceptional but a little brownish coloration of the brass plates. The same with a Bb accordion a few years ago. PS anyone interested in a full Bb set of Salpa's, good condition. Eventually some swap with a full Binci #1 C-set? - Nout