I dunno that fixating on the process node matters. KNC's product is a structured asic, just one step up from a FPGA hardcopy... and it shows it the power efficiency is half that being achieved in shipping products by others (bitfury, bitmain) on 55nm, and much lower than the 28nm products in preorder are claiming.
I was with Sam from KnC a few days ago at the bitcoin expo in london and he confirmed once and for all that the knc asic is not an eAsic nor any kind of shortcut design. it is a standard cell asic, the same as everyone else's. the only difference is that theirs shipped in early october so whatever decisions they took in the design to get it out so fast, were very effective and valuable...
and as for power efficiency, its not that bad. its 1W/GH at the wall. thats better than most bitfury boards .. most of those are > 1W/GH at the wall.