Is the most efficient speaker the best speaker?

"...--all other things being equal?"
Not bloody likely.

It depends on how much power you have. If your amplifier is a 2A3 SET I would say yes.

All things will never be equal. If the sensitivity is above 91dB, things are pretty good. 95dB and above, they can be driven even more easily. However, I love the sound of Maggies, 86dB sensitive, and Legacy Whispers at about 95dB sensitive, and some horns at 100dB plus, and have heard many efficient things which made my ears bleed. Thus, the bottom line is how well matched your amp is to your speakers, regardless of sensitivity. Jallen

NO. Still too many variables. Otherwise one technology would have won out long ago and that has not even come close to happening with any piece of equipment. Think it through.

I think with all other things equal, then I say yes it is best to have high efficiency speakers so the amp can cruise along in an effortless mode and for the right solid state designs class A all the time.

why not?