Andy,
I was gobsmacked that night at your home a couple of weeks ago. I have NEVER heard planars - most particularly, Maggies - deliver that sort of slam and impact! It not only rivals cone speakers, but betters many.
I doffs me cap - I give credit where it's due, it was a lot of work and expense for you.
ESSs are another matter again. There is something ethereal, almost supernatural about an electrostatic. I liken it to a harp played in heaven, and there is no doubt that on acoustic instruments and voice, the ESS is king. However, they have a pinprick imaging spot, and generally they lack slam and impact, and even with hardwood frames like your Maggies now I doubt you could remedy that problem, as the stator voltage is very limited by design, particularly in a humid climate. And driving them is a real pig - how is it such a transcendental concept looks, to the amp, like shovelling molasses? (Don't answer that, I know the answer!!)
In Oz a company called Whise has just produced an ESS/Cone hybrid speaker, actively powered. I'm hearing it this Wednesday, it will be interesting.....
Cheers,
Hugh