I've had a pre-production unit for a while. I guess I should post more impressions.
For whatever reason, at home they sound a bit rolled-off in the treble and a bit thick through the mids -- similar things I didn't like about the Oppo PM1. They don't do deep bass very well like planers with larger diaphragms do. So other than with the deep bass, the presentation is somewhat relaxed.
They seem to be quite brutal to drive -- they sound a bit asleep, so I'm going to play around with gear a bit to see what works well with them. The cable from the splitter to ear cups carries the sound of rubbing very badly too.