Here's a little trick you might try. I did it once and was truly amazed. Wouldn't buy an instrument without doing it now.

Have someone (preferably good who plays similar to your style) play the instrument at the far end of the room (store). Stand about five feet in front of them. Then gradually move as far away as possible and listen for the "decay". What I discovered was that several Collings guitars decayed much faster than several Martins. Discovered that my little 0-18 carried much farther than several bigger axes. The decay among Gibsons was pretty quick, but several Taylors seemed to hold their sound after twenty five or so feet.

Probably an important factor if you play strictly acoustically.

Rick