I don't think it's 400 that "swooped in"; HE4's are quite old in terms of Hifiman's headphone releases, it predates HE6 and HE500 both. Especially HE6, which was released just months after HE4, was the main reason why it never became that popular.
Have you modded your KSC35s (kramer / headband etc)?
I've been eyeing them for a while now, the kramer + headband modded KSC75s are fantastic but if there is potential of an additional big boost in SQ with just $30 more, I'm tempted to just snag a pair. Though IMO the price is a bit ridiculous for at least what quality of material you get with KSC35...heck it looks even cheaper than KSC75.
Edited by jerg - 11/15/12 at 8:52am