I know on my HE-560, the headband rubs up on the housing and does scratch it if you rotate them :/ I couldn't see much more on my housings under close inspection. Here's two pictures. Sorry about the quality, had to shoot with my iPhone in a bright, but poor, light :p
I'm sure a lot of Head-Fiers would rather the moving parts of the headband be metal rather than plastic, which would be my other complaint. I do know someone else did talk about the cable's hollowness, which is true as well.
I'm actually thinking about getting a cheaper, shorter cable for these: http://www.ebay.com/itm/HIFIMAN-HE-5-HE-6-HE-300-HE-400-HE-500-Headphone-Cable-Furutech-Upgrade-Cable-/121176877296? Won't do it soon, but will eventually, the 1/4" connector + adapter is about the length of my iPhone :p
Edited by tinyman392 - 5/8/14 at 11:00pm