Comparing the soundstages (headstage) from what I can hear with the HE-560 vs. the HE-6, the HE-560 is more "oval" while the HE-6 is more circular in shape (Not a perfect circle). The HE-560 has a wider soundstage, but less deep than the HE-6. The HE-6 has a deeper soundstage, but not as wide.
The ear pads effect the soundstage as well, I'm going to do a head to head with same ear pads as well. But those are my initial impressions about the soundstage.
By the way, you'll be getting the Oppo to compare, correct?