Just finished comparing the stock HE-500 and HE-560 cables on the HE-560s. There is a difference. Where the HE-500 cable has a lot of top-end energy, to the point of sibilance, if the song mastered that way (this with male vocals on Echo and the Bunnymen's "Stormy Weather"), and accentuates cymbals, esp. splashes, the HE-560 cable tames those sibilants very well. It also packs a bigger bottom-end overall, while not bleeding into the mids (or if it does, it doesn't bother me). It's a smoother presentation. I tested the aforementioned song, as I know I should be hearing some solid bass, and "Tom Sawyer" (24-bit 96kHz version), since it's a pretty neutral mix, and if the low-end is being accentuated at all, it'll show. The HE-500 cable doesn't really slouch on the bass, and maybe is a tad more accurate, but the over-accentuate highs can definitely detract.
I also listened to Hugh Laurie's "The Whale Has Swallowed Me" to have a non-rock, acoustic track, in there. I didn't focus on it as intently. The above stands for it, as well.
I should probably add that while the HE-560 cable has what I'd call a smoother presentation and a fatter bottom, details are not lost (or if they are, it didn't bother me). I was definitely listening for that with that cable. So in the end, with the HE-560s.... I'll stick with my DIY'd cable ... but only because I compared it to the stock HE-560 cable (for sound and ergonomics). For me, HFM definitely improved the cable along with the cans.