Thanks for the above. It has been a subject I've agonized over for a long time since there is just so much hype around the BRW thingy.....and after a while you start asking yourself (especially if contemplating ordering a new custom instrument as I did a while back) ''geez do I really want to pay Martin (or whoever) a 4 -5 thousand dollar premium for a few small thin slabs of BRW or can I live with IRW? and save a lot of money?" So I would think that anyone (obviously fairly well-heeled) contemplating a purchase of either a new custom Rosewood instrument or searching for older vintage guitars would want such a distinction made, in order to make as informed a choice as possible regarding the differences and benefits (if any) no matter how subtle. Otherwise you're basically throwing out hard earned money for a "look" rather than a real fundamental difference in tone.
Interesting about your comments about mahogany for cutting power and bluegrass....and I do agree with you. I honestly thing my old (straight braced) D-28 sounds more like a great D-18 than a 28. Because of the straight bracing, it doesn't boom or really resonate in the bass end (although the bass is there - just not to the degree that one is used to hearing it if they were using an HD-28 or one that employs scalloped braces.) But the mids and highs on it are astounding and just leap out at you. Is this sound typical of older BRW straight braced Martins?.....assuming those Martins are "good ones"?