Agreed with all the above and it sparks a little interest again.
Besides the Fostex brand the looks on this one is really attractive. Just beautiful and having owned the TH-600 I'm expecting the same comfort level and build quality. At the same time, by just reading Steve Guttenberg's words it's supposed to be a good bit warmer sounding than for example the HE-560. I was fortunate enough to audition the HiFiMAN hooked up to a Schiit Lyr and my Yulong D200 DAC and while really enjoyable, I don't think I'd want it any more romantic than that. This plus impressions in here is what's holding me back.
The TH500's are a warmer sounding headphone. Not quite as warm as the PM-2's which I heard a while ago, but I imagine fans of the HE-560 / HD800 sound would find them too warm.
I know it is not always easy but you have to try them to see if they suit your setup and music. I love finding pleasant surprises with headphones.