Hi gryfon, welcome. You ask a good question. In the months since this thread was truly active, I have heard that several manufacturer's are now claiming that the unobtanium SED winged C 6550's are superior to the KT120's. Among them is Ken Stevens of CAT fame. I can't say if this is true or not as I haven't had enough experience with the KT120's, however, I do greatly respect Ken's thoughts on these matters.