Electrolite
100+ Head-Fier
The SHP9500 was one the headphone that I really didn't like, very thin and dry sounding (un modded) so gave them away after a month but the person I gave them to really likes it so maybe its me that is the problem, LOL.
I've had my HD58X for a few weeks now and all of the non-audio nut friends who have heard them like them a lot but the ones who have decent/good audio system or better headphones say "you get what you pay for" since all will quickly pick up on the slight grain in the treble. While I do agree with you that its a matter of preference it seems to be more of experiences with other gear/headphones that matters more from what I've noticed with my friends.
I see your point but I don't know... There isn't a SINGLE headphone no matter how expensive it is where I never saw someone complaining. Utopia strange peak, HD800 soundstage isn't natural , SR 009 not enough bass or treble can be sibilant at times, Andromedas weren't that impressive, AEONs, Sundaras... doesn't matter... and on the other hand I also heard people saying they don't hear any of these problems at all.
And yes of course more expensive headphones are more refined but even if with a high-end mega blaster headphone people can hear grain or lack of bass or lack of resolution or anything I don't feel like all of those things are real problems on the headphone (yes sometimes the headphone really has a problem, I'm talking about more subjective issues where some can hear and others don't for example). I feel like they are just things that bother the person because it doesn't meet their preferred FR. So I feel like the HD58X grain isn't such an "issue" on the headphone, it's more subjective, some people get annoyed, others don't, I think it's just part of the Headphone's FR and not an innate flaw of the design.
Of course they aren't in my hands yet, maybe they really have a grain flaw but I saw people owning Stax and HD800 having no problems with the HD58X going with your argument of "it seems to be more of experiences with other gear/headphones that matters more from what I've noticed with my friends"