I have not really done a lot of A/B'ing with the HD800s, but here is what I think. The HD800 is another great headphone. While the HE-6 and T1 have similar sound with many small differences, the HD800's soundstage is significantly larger than the other two. I love a large soundstage and the 800s have it. The 800 has very slightly more upper and lower extension than the T1 and very slightly less upper and lower extension than the HE-6. The 800 is between the T1 and HE-6 in warmth, although it is closer to the T1. Like the HE-6, I do not find the HD800 to be as musical as the T1, more on the analytical side. The T1 is best with rock. I listen to a lot of rock so the T1 gets the most head time. Like the HE-6, the HD800 is better with jazz than the T1. Like the T1, it is better with male voices than the HE-6, but weaker with female voices than the HE-6. Unlike the T1, I rarely hear sibilance with the 800, although it does have more than the HE-6. The 800 is slightly easiest to drive than the T1, but still will not work well from an ipod or computer without an amp. The HD800 is much more comfortable than the HE-6, but only slightly more comfortable than the T1. The 800 is unnecessarily large to the extend that I sometimes feel self conscious when I wear them.