I have played/heard many J45s and D18s that I would put up against any rosewood guitar I have had first-hand experience with. Except one: Eddy Arnold's 1938 Martin D28 herringbone. That was the best guitar I have ever heard.
If you want some good data, ask luthiers who build many of the same guitar with different wood combinations. I know MANY luthiers who prefer mahogany over rosewood for their handmade guitars, but the customer traditionally wants some type of rosewood. Sure they have different sounding characteristics, but when I hear one luthier after the next say they prefer mahogany (for dreads, OM, OOO, SJ, all sizes etc), you need to at least consider the fact that they know their instruments best and what they think sounds best for their building style. Of course there are plenty of luthiers who prefer rosewood, but if you want good data, don't compare large manufacturers who use mahogany to their higher end rosewood guitars, compare handmade to handmade and see what you get.
Good question. You'll notice about $100 difference on some models for mahogany back/sides vs. rosewood, but I think that could change soon. Both Martin & Larrivee recently changed their entry level all wood models from genuine mahogany to sapele. Mahogany shortages could change the landscape to it being used less and/or costing more.
Back in the early 70's, I had my BABY stolen from me!!! My first "real" guitar, a 1967 Guild D-40, which I loved dearly... in the process of finding another guitar, I played a number of "antique" Martin guitars that a man in Costa Mesa, Ca had... and WITHOUT A DOUBT, the loudest, most amazing sounding guitar in his 15 odd Martin collection was a 1938 Martin D-18 (mahogany b/s). They're different than rosewood or maple, but still lovely, functional tone woods...
John Seth Sherman
I just received my Martin Elliot Easton and after playing it for about 5 hours I am amazed by the tone and volume the mahogany b/s and adi spruce top. There is no mud in the bass what so ever and each note rings out clear when playing chords. For me I don't regret selling my D35 to purchase this guitar...I just didn't bond with it and the EE feels like it's been with me for a long time.... Here are some quick pics, not the best though...
I have owned may highend acoustic guitars, Collings Bourgeois, Gibson and Martin.
I have a 1941 Martin 0018, A 1959 Martin D18, a 1942 Gibson J-45, a 1963 Gibson Hummingbird and a Collings C10. the thing all these guitars have in common is Mahogany back and sides and that they all sound fantastic.
I love the way the notes jump out, each one does it's own thing very well.
That said Rosewood guitars also sound amazing, very rich with overtones.
Many bluegrass guys love there D28's yet others prefer there D18's
I have a Maple back and sides Bourgeois and that guitar has the most amazing overtone I ever heard , mot bright and snappy as maple guitars are known to be.
each one has it's own voice, the question is what matches the sound in your head, what is it that makes you happy.
Bert Jansch played a crappy Yamaha and made it sound like God.
For me, if I could have just one guitar it would be Mahogany back and sides with a good spruce top, but that is just for me.
Check out the video of Richard Hoover of Santa CruzGuitars at the Artisan Guitar website link below. Click on the videos bar at the top. Be prepared to be "schooled" to the "inferior mahogany myth" and many others. Most worthy information.