high-efficiency loudspeakers

I own a pair of Zu Audio Omen Def. At 100dB, these speakers are very easy to drive. Sound wise they rock the house! They have temper and attitude; I wouldn't call them "accurate" or "transparent", but rather full, dynamic and fun to listen to. 

Did anybody  who listen above mention LS  can say about  tendency 
high efficiency loudspeakers
to make thinner sound ( i dont mean lower bass) compare to
traditional 3 way speakers?  Thinner sound  especially made
piano sound smaller and man vocal also 

I am driving my Heresys with a pair of 40 watt mono amps and it is more than enough power to play louder that you could endure for any length of time.....  I don't really play it loud, but the dynamics and effortlessness to drive allow pretty much any amp .

The Klipsch are also full, dynamic, and fun to listen to.   

Charney Audio!
Have owned a pair of Maestros 100db (Omega RS7 driver) for over a year and I’m still amazed at what I hear. Clean open 3D presentation with deep articulate bass to boot. Beautiful to look at and wonderful to listen too. Charney also builds Lowther 103db and Voxativ 103db based Companion and Concerto that are a clear step up form the Maestro. Each of the tractrix theory designed horns play well above anything out there in respected price ranges...go listen at Charney in NJ well worth the trip!

I have Zu Definition 4s and like them a lot. I drive them with a 300b SET. I have also heard and liked the Audio Note AN-E. There is an online commentary about high efficiency speakers: http://www.high-endaudio.com/RECENT.html#Nov