Klipsch K Horns (the new AK6)

Yep if I had the right space I would value owning these and do what it takes to nurse them to perfection. 

High efficiency and load are of course two different things.

Getting a good match is always critical but the speakers that will work well with the widest variety of amps are those with an easy load, like Daedulus and Fritz, not necessarily those that are high efficiency.

Efficiency only determines how loud things can get per watt.

An easy load also means "better mileage" per watt which can translate to speakers going louder better than others with difficult load yet similar efficiency specs.

High efficiency speakers often get a bad rap because they have potential to easily sound the most wrong if not driven by the right amp. But with the right amp....... Not for the faint of heart.