I knew that would come up when I posted.
The HD700 are overall more balanced with a treble peak that is smooth, not edgy or fatiguing, especially with Amperex tubes. Highs took a long, long time to smooth out. Bass quality and mids are crazy good. Can get edgy with the different tubes. I had the HE400 for for or 5 months before I got the HD700 and they never quite sat right with me. Don't get me wrong, I do think they're impressive. They're my first recommendation to people looking for a headphone in that price range.
Edited by MickeyVee - 1/23/13 at 5:39pm