I will post am documenting changes in sound according to hours and using a variety of equipment. The first 5 hours are well documented and it will see burn in overnight tonight with a listen in the morning.
Right now I have my Home setup (in my sig) working in the same way with the P-51 in place of the SSMH to test how well it really can control these power hungry (current, not gain) headphones. I have heard the P-51 powering an R10 and I have heard my same headphone through that setup at the meet in Chicago (they have VERY similar qualities with an edge at the time to the R10 for greater fullness and better bass (not detail), granted I put the cable on that morning...). I just made and installed a passive output stage on my Zhaolu (Mucho better IMO - thanks cotdt

), but the new caps in the Zhaolu have only seen ~14 hours of use and need more time to reach full potential. Primarily though, the listening has been focus through my iPod to "6wire Special" to P-51 to my recabled and modded ESW9/recabled FreQShow. It is a portable amp and would likely be in this sort of scenario given the price level.
This amp has about 70 hours before I would feel confident in enough to write any real impressions or anything. However, do feel free to PM me with any questions.