In your opinion, which one looks better? Is one more comfortable?
I like maple just because I only have rosewood gear. My rosewood fretboards are all nice, dark pieces though. Wood grain is very nice.
Realised how far off the original OP I actually was.. I followed a secondary OP which made it more a 2P or TP...
Back to Fretboards!
There is talk of resonance and sustain.. rosewood being a softer texture than maple which affects resonance in... yawn.
If they modify sound that much, we should also consider calloused vs soft fingertips.
There has to be something in it...
there is this from stack exchange:
Maple boards are typically placed on Swamp Ash or brighter wood bodies and it lends a snap to the tone of the guitar. Rosewood is known to be much mellower, and usually makes it's way on mahogany bodies and necks. They definitely feel different too. A maple neck is harder and feels very smooth under your fingers, while rosewood has some sponginess to it due to the porous properties of the wood.
There are plenty of guitars out there that don't follow these traditional approaches so your mileage may vary. As to why they are chosen? I'd say tradition, along with the availability of the wood itself. It is however well known that woods lend specific tones to an instrument, so possibly years of experience and use by high quality luthiers have lent to the reputation of maple and rosewood. There are plenty of other fingerboard woods out there to choose from, but these two seem to be industry standards.
But some guitars just look ODD with a different neck... the tonal differences should be acknowledged, but they use what they use, and we play what we play. I have both and take no preference...