I think that Brazilian Rosewood is overrated. Perhaps we like the tone of BRW guitars because they are all older than the IRW guitars we are comparing them to. Older means better tone, no matter what the wood.
Luthier, John Greven, says that the density, not the fancy figuring of the grain, is what gives the wood its tone. He thinks good IRW sounds better than BRW, and I tend to agree with him. I have a very nice IRW Martin that will sound fantastic in thirty years or so, and it cost thousands less than if it were made of BRW.
I also think Mahogany is a really good material for the back and sides. I can't decide whether I like my 36 year old Mahogany Gibson better or worse than my new IRW Martin. I guess I'll keep them both.