I really, really like the top end. Being reasonably young and capable of hearing to about 18khz, I'm somewhat sensitive to grainy treble. Even if there isn't musical information above 15 or so, which I thoroughly believe, there is room for error. I really feel the treble is much more natural on the ECD-1, without losing any detail that I've noticed. Hi hats and hand claps sound excellent, both in timbre and in soundstage.
The midrange is what is often praised on this unit, and while I have no complaints it doesn't strike me as being revolutionary. It isn't scooped all to hell, which is nice. Reed instruments have a lot of bite, which is really what I listen for.
I didn't dislike the DAC1, I just didn't feel it was an improvement enough over cheaper gear (0404, Oritek, VDA) I had enjoyed, so I sent it along. The ECD-1 is staying, both for its excellent sound and its pleasing look.