Had a chance to do a quick listen to a HE500 in a recent meet, and was very pleased with the way it sounded. The midrange and treble has a very special quality to it as it is bodied yet being very clear at the same time, which is like the HD600 but clearer, airier and planar
Definitely my favorite Hifiman headphone yet, though I have yet to listen to HE6 out of a speaker amp. Kinda like a HE5LE (which is also well-balanced) but make it more melodious and clearer in the upper mid-treble. Soundstage is not super big, but this is actually a good thing since you can listen to that beautiful mid quite close. Comfort is not bad for my head, unlike the HE6 or LCD-2.
I just wished that Hifiman could have priced the HE500 at $600ish and it will be the king for that price and a very musical one indeed. For my own money, I would still pick the $1000 LCD-2 and its intense bass over the $900 HE500. Plus, I don't want to buy a $900 headphone that might be replaced with something better in less than year. Who knows if the HE1000 is already in the works.