Bought one earlier this week from MusicTeck and they just arrived.
I normally don't put too much stock into burn-in, but with my R-2R experience, I've seen some subtle changes over time with burn-in and also with just leaving them on. Now gotta figure out how to keep this thing warm.
Initial impressions out of the box:
Warm lows, generally soft sound. Upper-mids is slightly peak with a bit of harshness. Treble is roll-off but gently and not bothersome. (generally sweet).
Using the Unique Melody MEST Custom with 4.4mm balance cable.