Is the most efficient speaker the best speaker?

I believe it was Earl Geddes who said, "Science is not a democracy".

What he meant is simply this: Facts are facts and are not subject to voter approval.

No matter how many fools choose to disagree with him, Atmasphere remains correct in his statement.

You guys are missing some key points. All speaker designers want to have high efficiency but you can't always get it without compromising something else, like frequency response or a changing impedance. As in most engineering, you have to make choices and it's up to the designer to make the changes he/she wants, efficiency is one of the first to get compromised.

Prove it.

You know guys, it seems to me that the op really just wanted to know if if efficiency is something to seek out.
We have all blown this up. I have built speakers from 84 db sensitivity to 99 db sensitivity... The all sounded quite good in their own right. In my experience, there is no requirement of high sensitivity to make really fine sounding speaker, nor do really high or low sensitivity speakers sound one better than the other. They do have different requirements for power and placement and what type of amp that they sound best with.....
The good news is that the ops question as written is truly impossible.

Efficiency in of itself is a good thing.

But alone, efficiency means nothing except volume.

I think we can all agree there is more to it than just that?