If you remove a the octave strings on a 12 string acoustic how would the guitar then compare to conventional 6-string, acoustic guitars? 12 strings have bigger bodies, would they then be analogous to some of the bigger body acoustics, like a Taylor Grand Orchestra for instance?
The neck of a 12 string is wider than a regular acoustic, so people with particularly large hands might like that.
The overall build is often also a little thicker and sturdier, to withstand the extra tension, and therefore the overall resonance of the guitar will be a little less.
But having said that, I think that the difference between one brand and another, or the difference between cheaper and better models is going to be far greater than the difference between 6-string and 12-string versions of the same model.