I just got home from a meet where I finally had a chance to revisit the HE-400. Call me impressed! Tight, deep, controlled bass that I find better than the LCD-2 and HE-500. Sparkly non-fatiguing treble like I've never heard from a planar before, and flat mids that aren't too warm like the HE-500 and LCD-2. These aren't as refined as the LCD-3, but I think the FR might be more to my liking - a little more fun sounding.
I was in the first group who pre-ordered it last spring for $349 and was so disappointed in the sound when I got it. I kept them for a couple weeks hoping they (or I) might settle in a bit, but it didn't happen. During this time, reports of failing drivers started coming in and that was the nail in the coffin for me. I decided to return them for a refund.
Now I'm feeling a little conflicted. I really like the HE-400 - a lot! But can I live with being "penalized" $50 for re-buying a headphone that now sounds like it should have from the beginning?