I always prefer to buy a HD800s as a upgrade to my HD700 system, until I owned a sr-L500 and a good pre-amp...
I think my current L500 setup can be compared to a HD800 + HDVD800, just having less bass. At least clearly better then my HD700 using the same setup.
One problem with Stax amps is that they are good power amp but not a good integrated amp. The Stax amps not driving Stax headphone as good as 3rd parties integrated amps.
On contrary, there is less choice of 3rd parties amps for electrostatic headphone and they all sounds great. I don't need much effort to decide which one I should buy.
I know I can get rid of those Sibilance with a mod, on the other hand, to reveal the true ability of HD800s, lots of time and money are required.
Given that I have already ordered a KGSSHV from a DIYer, I am at a point that unable to decide whether I should go for SR009 or HD800s because the cost for making HD800s sound exotic is close to the price of getting a SR009.
Ultimately, If Senn market a new electrostatic headphone at the price range like SR009, I will definitely put all my time and money on it, forget about HD800s and SR009.
After all, there is no return once you know how fantastic can a electrostatic headphone sound. I mean HE-1
.