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

Low-eff designs can suffer from dynamic and power compression. It's not possible for those designs to replicate the natural dynamic range that real music has and if you play those designs at a higher SPL level many have power compression.  If you can deal with reduced dynamic range and need a small speaker maybe low-eff is for you. If you enjoy the dynamics that real music has and want freedom from power compression at higher SPL levels and can deal with a larger loudspeaker then hi- eff most likely is best for you.

Johnk is not wrong.  High efficiency speakers are much more dynamic sounding, at least in part, because they suffer less from thermal compression.  When playing at any given level, the higher efficiency speaker will be passing much less current and the voice coil will not be heating up as much as is the case with a low efficiency speaker.  That heating of the wire causes an increase in the resistance of the wire, which means, when there is an even stronger current that is suppose to flow, the amount that can flow is reduced and not proportionate to what is supposed to flow.  This results in compression (less than proportionate increase in the current flowing and the resulting movement of the diaphragm).  

The increase in dynamics of high efficiency horn systems is evident even at quite low volume levels.  In fact, I tend to find that it is MOST evident when playing music at modest levels--high efficiency systems sound more lively.  

@Johnk. My apologies Johnk - I misconstrued your answer.  We both agree that high efficient speakers are more dynamic.

We are all basing our opinions and experiences using " reproduced / recorded " music. As I have said many times, this alone, creates many challenges for us as listeners. It boils down to the specifics of what YOU want your favorite performers to sound like, in your own listening room. Debating on these threads, simply shows how different we all are as listeners. Every system....every part of every system ( room being critical ), will be taxed in some way....great in some areas, and just ok in others. This is why so many listeners I communicate with, only listen to greatly recorded music ( things like Sheffield Labs, just as an example ). We make the decision of what we like, what we want, and how we think it should sound. My system allows me to " forget " the system, and creates a connection between me, and who I am listening to. On another thread, Ron Carter was mentioned, and there were three points R.C. discussed as being very important for his reproduction of his system. # 1 : was to allow him to hear the sound of the studio space; # 2 : was to allow him to hear the sound of the live venue; # 3 : was to allow him to hear  his " playing " of his instrument. For me, number 3 is ALL about our pursuit of musical enjoyment. Whatever works for you......Enjoy ! Always, MrD.