^^Fit issues are quite possible with all the HFM series. The first he-4 I bought, used, came from a guy that must have a massive melon (hope he's not reading). The cups didn't even touch my face, seriously. I bent and bent that headband but never could get it reshaped so that I got a good clamp. Therefore the hp's never sounded quite right.
It bothers me how seldom people mention their physical changes to a headphone in the FS forum. My HE-400's have enough grip to have the pads touching each other when not worn. I see people selling HE-400's on the FS forum that (at rest) have 4-5" between the pads... yikes!