What is your take on high efficient speakers vs. low efficient speakers?

@lg1 You’ll need almost a full month in order to evaluate the speakers. The human brain can be very tricky and deceiving in the short term. 

To my ears high efficiency speakers have an agility and realism not present in low efficiency speakers. Agree that lots of time needed to sort out the sound, listening tests are hard.

@larryi That's what I wonted to hear from you.  You're on the right track. 

Here is my take on high efficient speakers. They sound great when done right. Unfortunately, it’s not that easy to design an efficient speaker. That’s why speaker companies rather make inefficient speaker by complicating the design. Simple is better but it takes longer time to implement - that’s how I see it.

As someone above mentioned, most of these high-efficiency systems do not do really deep bass.  That is one of the tradeoffs that attend going this route.  For my taste, the very best woofers for a high efficiency system must be very agile to match the other drivers.  This typically means very light paper cones, and somewhat limited excursion (I particularly like drivers with pleated fabric or paper surrounds).  I've heard systems with twin 18" woofers per side that were still a touch limited in very deep extension, but, I really did not care much--the bass was clean, fast, and had "tone," which is more important to me.  I have no interest in a subwoofer, and several of my friends who are horn-based system experts say that subwoofers are NOT the way to go. My system has very modest twin 12" woofers per channel (pleated fabric surround, alnico magnet) in a Jensen-Onken bass reflex cabinet; it does not do deep bass.  With every system, you have to live with some limitations.