A long thread so haven't read it all. My personal opinions is, there is no difference, a lot of us wouldn't even know whether it was a sharp or flat key without an instrument to find the key on.
On the other hand along the same lines, I do believe that certain songs or tunes sometimes sound best in a certain key, probably due to the fact where the melody falls within a scale range, for a song probably takes the vocals of singer into consideration, and for the tunes the instruments play a big part.
Last edited by musiclover; 02/03/19 06:27 AM.