Felix, I agree with the consensus that a 12-fret will sound warmer / fatter and more "mature" or broken-in versus a 14-fret. The 14-fret version will often have a snappier and more projecting character, but that can often be attributed to longer scale length too (25.5" versus 24.9"). Most luthiers believe that very little sound comes from the cutaway area, since that part of the top does not move much. And the loss of internal volume is a very minor effect too. (I could argue that the lack of internal symmetry minimizes the cancellation of certain internal sound waves). It is impossible to prove that a cutaway void either contributes or detracts, since no two guitar tops are ever exactly alike. Even in my now preferred carbon fiber guitars, it is difficult to compare a cutaway and non-cutaway version of the same model. Carbon fiber guitars should theoretically have exactly the same tops, with lay-ups far more consistent than any two tops - even adjoining flitches of the same log.
Loudness is highly subjective. I have been working in acoustics and sound measurement for 37 years now, and I can tell you that quantifying "loudness" is no easy matter. Entire textbooks have been written about just that subject. My $6000 sound meters can measure to 1/10th decibel reliably, but exactly how that translates to perceived "loudness" is a whole other kettle of fish. Basically if you believe that the non-cutaway is louder and/or sweeter, then that is the answer. Beauty is in the ear of the beholder....