Unfortunately, my high end listening experience is limited. I do like these more than the PSB M4U2 which is more neutral but less dynamic and fun. I think the D600 is far superior to the AKG K550 and is comparable to the Ultrasone Signature Pro and Edition 8 which are both much more expensive.
Wow Craigster75, You and I do have rather different tastes. My apologies for the past few weeks telling you to wait, wait, wait, till the various brands and models to be released on the market. But I understand your requirements more now.