I owned several 555s and for the money,they could not be beat.Nothing else at anywhere near the price would drive my Infinity Kappa 9 speakers like the big Adcoms.BTW,I preferred the original 555 to the mk.II version;and,also liked it better than the 5500,5800 and 5802.With proper system matching and cables harshness was not a problem.
Larry
Larry