It's a hard-sell, the further you get away from 100% efficiency. In this day and age of "green technology", every watt seems to count. I'm still skeptical how much wireless power will get implemented past a few feet. That's just my gut feeling on the subject. Take it for what it's worth.
Everyone is still skeptical about it, but from calculations and measurement I can tell you that efficiency will be close to 100% over meters and miles
See this vid:
YouTube - Wireless Power
The problem is they use the resonators in the same plane. I've found the optimal placement.
As you can see in my figures, the number 3 is indeed essential to the shape . It was tesla's Nr.