I've encountered that description for other electrostatics. In fact, I owned a set of Acoustats (actually, three sets crossed my path). The best of the bunch was, IMO, the 2+2s, which were tall and narrow. So you didn't get the vertical 'beam' (although the horizontal remained a problem). One day an acquaintance with a good ear came to listen. He casually mentioned that the Acoustat's imparted a 'plastic' credit-cardish kind of sound to the music.
Well, that did it for me. I never noticed it before, but from then on all I could hear was his plastic credit card analogy. You know, the sound you get when you pick or ping the card. Shortly thereafter I sold them. Shortly thereafter I sort of missed them. Nothing is ever one size fits all, it seems.
As an aside, in the US, original Quad distribution was (as far as I know) via Bud Fried, a hi-fi salon owner in Philly. He imported them, sold them through his store front, and probably mail order-- I don't know about that. This was in the mid '60s, I believe. The few who owned them might use Paoli modified Dynaco amplifiers. McIntosh or Marantz tubes, and so forth.
When four channel Japanese systems were becoming (not so) popular, Quad ran small ads in Audio magazine warning people that the word 'quad' was trademarked, and had nothing to do with four channel sound hardware. The company argued how in the vernacular, the press should stop using the word 'quad' to mean four channel audio. But by then it was too late, and no one cared. No one cared for four channel, and few had ever heard Quad ESLs. Besides, Quality Unit Amplifier Domestic sounded too much like what you'd find in a sealed can, in a K-Ration.