As I experienced myself yesterday night, a lot depends on the music you're playing too.
I listened to Ars Arcana: The Savage Tongue yesterday.
While I usually prefer my HD800's and value them for their clarity, they just didn't seem to do this album justice.
They did nothing wrong, it's more what they couldn't do: bring life into this music.
Playing something like Rob Wasserman's Duets makes me take out the HD800 since these bring out the detail that just has to be heard on a CD like this.
The D7000 on the other hand made the experience much more intimate, more musical and enjoyable. I played the CD twice over with them.
The HD650 simply couldn't cope with this music, it was too much for it.
I wouldn't really say the bass was distorted, rather it tried hard to give me bass that it couldn't handle. The kind of bass that I refer to as boomy, blooming, muddy.
I think the Stax will be a wise choice, as they seem to have characteristics I value in both the HD800 and D7000, from what I learned from this thread.
I must thank you all for the many replies and the very helpful info.
I will certainly audition them at a dealer, and probably order them in the US.
Has anybody heard a 727II amp yet? Or had a chance to compare it with the KGSS?
And I believe the KGSS DX is a special version of a previous KGSS, not the current one?