Difference among Burke C brass, alum. & composite?

As I’ve mentioned on the board, I really like the sound of my Burke C Brass Pro. But, I don’t like brass whistles so much.

What is the difference in tone among these three materials in the C whistle? I did a search and read what people have said about the D but since the C (at least in brass) is such a different sounding whistle, it would be great if someone could do a comparison for this key in particular? Anyone with such a collection?

Thanks much!