arc has, in recent (the last 10-15) years continued to make their sound more extended into far reaching treble and bass, providing a greater sense of speed, while maintaining the lovely midrange and soundstaging magic
c-j has as well ... especially from art to act to gat... i have personally gone from pv-14 to prem 17ls2 to prem 16ls2 to et-5 and now to et7-ii -- each step offered decidely more transparency, bass solidity and slam, with an attendant reduction in the old 'rose-colored glasses' presentation...just like audio research, the tube magic is still there in the critical midrange and for spatial presentation, but at the same time, allowing the listener to hear into the music much more than before
its my opinion, one shared with other owners of higher level arc and c-j units, is that the sound of these two companies have been converging for some time into their version of a ’more modern sound’