Yeah, those Tesla Beyers have been mentioned to actually be more fatiguing than the older Premiums. That's why I lost interest.
As for the planar soundstage, I basically mean the depth of the sound, even in stereo. It sounds more rounded off and less linear. It's unlike any dynamic I've heard. It certainly doesn't reach out as much as some of the better dynamics though. I just love their presentation for music though.
As for the Kingsound... having a pretty heated discussion with some of the Stax 'Mafia', who have basically blasted the headphone since before it's release. Now that it's out, they're basically calling it crap. While I take their biased impressions with a grain of salt, I'm not really interested in spending so much for a specialty stat. I'd prefer something more universal to use.
I honestly don't even want to ever spend that much for headphones ever again, anyways. Something between the HE400 and HE500 in price and signature, with better comfort than both, and planar would be ideal.
I think if they made a lighter HE500... I would jump at it. I'm just tired of Hifiman's design. They need a new design, with pads as good as the HE4's, and weight like the HE4, but not as hard to drive. Like an HE-450...