Just a few comments as a card carrying orthohead.
An assumption being made is that push-pull planar magnetic is "better" than single ended. I am sure that you recognise this theme 'P-P vs SE' as it has been beaten to death in electronics which obviously has different connotations but ultimately does bear some relevance to the subject at hand. Push-Pull offers more power when considering the same source of power whether a tube, solid state output device or magnet structure for a planar magnetic driver. Planar magnetic drivers have classically evolved as push pull due relatively poor magnetic strengths of early magnets. Take the Wharfedale isodynamic which uses good old fashioned rubberized "fridge magnets". If this headphone were any less efficient it would be relegated to obscurity ( not that many people have even heard of it ). Magnet technology has evoloved along with everything else, ceramic magnets and some of the more exotic materials that vintage orthoheads silently get off on, all had one ( perhaps 2 ) goals in mind. Greater strength to improve efficiency and more even polarization. Problems both real and theoretical exist with push-pull, the most discussed is probably the resonances derived from the cavity created by the magnet structure. There is a white paper out there that discusses some of the resonances / driver ringing that can be exacerbated by the dual layer of magnets and one of the reasons several planar magnetic speaker manufacturers looked into the use of single sided drivers. ( yep, I am afraid this is not a JPS original ) . If you scour the ortho thread , you will see some experiments conducted with some of the vintage drivers by converting them into single sided drivers. Some more successful than others but nothing of such groundbeaking discovery that more people were inclined to universally implement it. The real pièce de résistance of the Abyss is the custom single piece magnet. Not that I am down playing the real R&D that went into the driver ( I have not seen it but what tidbits I know, it is at the technological forefront of its kind ). To have a single, powerful magnet that can be perfectly aligned to the driver ( and not have to worry about the second magnet shifting and possibly causing all sorts of polarity and polarisation issues ) , is a huge advance in this technology. It does not follow "previous art" and sometimes stepping out of the box allows for positive innovation. Does this mean that the single ended driver is free from all of these problems that the more classic P-P driver suffers from, in an ideal world perhaps, but this is why I chose to use the word "exacerbates" . JPS is a new kid on the block and took many of us by surprise but that has been the nature of the new planar magnetics, Audeze was known to the ortho crowd but no one anticipated HiFiMan to have a product at the same CanJam that the LCD made its debut ( well no one would be a far stretch, there are always a few who follow these developments but are generally sworn to secrecy or have to sign an NDA ). JPS has access to materials and industry developments through their manufacture of exotic cables and even though they are not speaker engineers, this type of knowledge can be attained through consultation and research. The acceptance of their product is for the consumer to decide, be it based on price, design, audio quality. If what the Cable Co. says is true, their first run has sold out already, so clearly there is more than just peripheral interest.
I have only heard the abyss as a prototype at a trade show and what I heard was very encouraging.
..dB