Unfortunately I have to agree. Today I just noticed that my HE-500 started to rust. My HE-4 has rusty screws so I cant even replace them while the HE-500 is rusting on all metallic parts. I am very sad as they are my favourite headphones and I thought I would settle down with them as my final cans. I cleaned some rust away but the colour was removed with it so the grey-silver paint is now golden-brown on some areas.
The HE 500 is a great start for those who want to jump into Orthos but Hifiman should improve the build quality.
I ain't spending $700 for rusted screw, loose fittings, cheapo cables etc. The HE6 seems to be better built.
Beyer still wins in the build quality department. Their mid range stuff are still built like Panzers